Talk:2013 Group 4 Project

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2013 Projects: Group 1 | Group 2 | Group 3 | Group 4 | Group 5 | Group 6 | Group 7

  1. Do not remove this notice {{2013 Project discussion}} from the top of the discussion page.
  2. Newest student comments should be entered at the top of this current page under the subheading "Student Discussion Area" (you cannot edit the sub-heading title).
  3. All comments should begin with your own signature button, that will automatically enter student number date/time stamp.
  4. Do not use your full name here in discussion, if absolutely necessary you may use first names only.
  5. Do not remove or edit other student comments.
  6. Use sub-headings if you want to add other draft information, images, references, etc.
  7. Only your own group members should edit this page, unless directed otherwise by the course co-ordinator.

Group Assessment Criteria

  1. The key points relating to the topic that your group allocated are clearly described.
  2. The choice of content, headings and sub-headings, diagrams, tables, graphs show a good understanding of the topic area.
  3. Content is correctly cited and referenced.
  4. The wiki has an element of teaching at a peer level using the student's own innovative diagrams, tables or figures and/or using interesting examples or explanations.
  5. Evidence of significant research relating to basic and applied sciences that goes beyond the formal teaching activities.
  6. Relates the topic and content of the Wiki entry to learning aims of cell biology.
  7. Clearly reflects on editing/feedback from group peers and articulates how the Wiki could be improved (or not) based on peer comments/feedback. Demonstrates an ability to review own work when criticised in an open edited wiki format. Reflects on what was learned from the process of editing a peer's wiki.
  8. Evaluates own performance and that of group peers to give a rounded summary of this wiki process in terms of group effort and achievement.
  9. The content of the wiki should demonstrate to the reader that your group has researched adequately on this topic and covered the key areas necessary to inform your peers in their learning.
  10. Develops and edits the wiki entries in accordance with the above guidelines.

Week 2 Project topic selection, preliminary researching on the topic.

Week 3 By the next practical class (after the mid-session break) there should be sub-headings and content on your actual project page and interactions between individual group members on this discussion page.

Week 4 Each group member should now have selected 4 papers relevant to their section of the project. These, or any other papers, can now be used to generate content (text, images and tables) within the project page. Students can also work on additional sub-headings on the project page.

Week 8 Peer assessment of group project work.

  • Each student will carry out an assessment of all Group projects other than their own.
  • This written assessment should then be pasted on the actual project discussion page and your own individual student page.
  • The peer assessment for each project should be concise and include both positive and negative critical analysis of the current project status.
  • The actual assessment criteria (shown above) can be used if you like.
  • Each student assessment should be your own work and be completed before the next Lab.

Peer Assessment

Introduction:

  • I feel as though the actual spindle apparatus should be talked about more. While the definitions of mitosis and meiosis are good, I suggest that maybe these could go in the glossary instead and focus more on the role of the spindles in cell division. Maybe also give a brief overview of what the page will discuss
  • Images accompanying text are great, showing the activity of the spindles and breaking up the text
  • I think that the large image at the beginning of the page could be used in the body of the project, or made a little smaller if you want to keep it at the top of the page
  • Images have all info required but need to fix up the referencing
  • This section lacks referencing

Historical Research:

  • This section is very well researched
  • Don’t think that the subheading in this section is necessary
  • There are no major gaps in time so it flows well. However, some of the sections could be summarised a little more and may want to reconsider the first few dates and discoveries, could start with the discovery of the spindle
  • Some of the discoveries lack referencing
  • I like how images have been incorporated into the timeline, however, they should be referenced properly
  • May want to include more recent discoveries

Structure:

  • This section contains a substantial amount of information, some of this could be better off in the function section or summarised more
  • Good use of images which all contain the necessary information

Function:

  • This section is very well researched, it does however repeat some of the info previously mentioned (particularly the first paragraph which isn’t referenced)
  • This section could use an image or two to break-up the text, perhaps one from a previous section
  • Feel as though some more referencing is needed

Mechanism of Formation:

  • Good use of subheadings in this section
  • Good balance of text and image. Some of the parts of the images could be explained in own words
  • There appears to be some repetition of some info in the opening paragraph with the previous sections

Current Research:

  • The different research studies have been explained thoroughly and summarised well and the accompanying images contribute to the section well.
  • Maybe could provide links to these studies
  • Could add some future research topics?

Complications:

  • Interesting section to include, well summarised and broken up

Overall, this topic has been researched well and there’s a good balance of text and images. There appears to be some repetition in the structure, function and mechanism sections particularly in the opening paragraphs and there’s some overlap in the structure and function sections

Group 4 Nice picture at the beginning of the page, I think the introduction should be about the spindle itself rather than cell division because we all know the phases this far along in our studies. History table is well written, I think you could put the pictures outside the table to make it a bit nicer, and there are some rows that don't have any text. Structure is really well written and laid out, genes and proteins listed which is good. Function is well explained and broken down into sections. Formation is well written as is the rest of the project. Diseases are nicely broken down too so it makes it simple to read and understand.

I like the way you use the diagram to explain the mitosis event. The table is well presented and just need to fill in the 1980s part. The diagram in the structure section could be adjusted a bit so that the word "during" isn't separated from the rest of the sentences. Other than that it is good. Overall, the content is logical and well-presented. In certain areas the between diagram and text is good, which makes it interesting.

Group 4
Introuction

  • Good introduction, Very detailed. Relevant and interesting pictures
  • Although just an introduction, citations are still a good idea.

Historical research

  • Very detailed history of the spindle apparatus. Well written too
  • Pictures within the table look great
  • Colours are pleasing to the eye
  • Just be sure to add info for ‘1890s’ and either add information to the last two blank rows or get rid of them.

Structure

  • Well written, informative. It could help if it was a little more succinct but overall, this wasn’t a big issue for me.
  • Good citation

Fuction

  • I really liked this section. It was structured well, was informative and was easy to read (whilst still being very scientific).
  • Subheadings worked well
  • Adding a picture or two would help break up the text

Mechanism of formation

  • Good information. Similar in style/structure/detail to ‘structure’.
  • Similar to ‘structure’, this section can afford to be a bit more succinct. It was a bit much to take in.
  • Pictures worked well. Relevant and aesthetically pleasing.

Current research, complictions

  • Overall, not much criticism for these sections.
  • Well written, good use of referencing.
  • Good structure and succinct enough to read.
  • Pictures looked good and were relevant to the information.
  • Good use of glossary – Not too long and defined relevant words.

Peer Review

The first picture is really good, I actually like how it’s a big picture with no text because it makes the person who is looking at the page focus on what the spindle apparatus is.

Although the introduction gives a good introduction to cell division in general, there could be more specifics of spindle apparatus and why it’s an important component of cell division.

The History table is good and gives a lot of relevant information, but there is text missing from the 1890’s box.

The section about structure has a good balance of text and supporting pictures, while the function section could use a few more images. I also noticed in these sections that some paragraphs had no references.

The current research and complications sections were interesting and informative.

Overall, it’s a good page and the images help to explain what you’re writing about.


Conversations/Comments from Group Members

--Z3369112 (talk) 16:41, 16 May 2013 (EST)Instructions for peer-marking assessment will be listed where all the individual lab assessments are posted. There are 7 group Wiki pages. Each student must peer-mark the 6 other group Wiki pages and put it on your own individual page (as per all the previous lab assessments). How to peer-mark? Start by reading the group page (does it make sense? is content repeated? are there enough pictures?), list down the positives and negatives of the group, check the structure of the Wiki page, if it contains the basic subheadings and images are properly referenced, etc. Course coordinator does not expect too much (half a page is a maximum limit). Individual assessment is course coordinator reading your comments and seeing if you've done a good job. Needs to be completed by next week's lab, Thursday 23rd May 2013.

--Z3369112 (talk) 16:19, 16 May 2013 (EST)During today's lab session, groups were given the opportunity to discuss and finalise their group Wiki page before the peer-marking assessment. Some suggestions we all came up with was adding a table of protein functions to the Current Research section, fixing the multiple references and adding more pictures. To solve the problem of Editing Conflict, it was advised by the course coordinator to edit the Wiki page section in one's individual page and then only paste it into the group Wiki page.

--Z3376548 (talk) 20:36, 15 May 2013 (EST)yeah, it's a good idea to add more stuff in, I will look for more function related sub-components in advance!

--Z3376548 (talk) 20:36, 15 May 2013 (EST)I am thinking about placing them in a subsection "current research and past research"...

--Z3376548 (talk) 20:36, 15 May 2013 (EST)It has more for me to talk about as now I am focusing on the functions of some un-replacable substances that aid spindle formation, as in like, the function they have to stablise spindle anchoring, etc...

--Z3376548 (talk) 20:36, 15 May 2013 (EST)hello group fellows! after spending time on my subsection which is "function of spindle apparatus" , I found nothing more to talk about but just it is there to pull two chromotids apart........

--Z3374392 (talk) 15:04, 15 May 2013 (EST) I think we should add more information on dynamic instability. Perhaps in the mechanism of formation section?

--Z3374392 (talk) 22:08, 11 May 2013 (EST) I added more information on complications. I know there are reference double ups atm. I will fix those up soon.

--Z3374392 (talk) 18:51, 10 May 2013 (EST) I am adding more information on structure today. Also, I think it would be great to include a nice image in the intro and perhaps a few thumbnails in the timeline.

--Z3374392 (talk) 23:14, 10 May 2013 (EST) I think it would be a good idea to have a section on the complications and diseases. I am starting this section now. Alse, the last reference I've used in the 'structure' section won't format properly. I don't know what's wrong! Can someone please try and fix it? Thank you

--Z3374392 (talk) 15:28, 9 May 2013 (EST) In today's lecture, the spindle apparatus was discussed. There was mention of the astral microtubules, kinetochore microtubules and polar microtubules. This is a very important part of the structure and I have yet to mention. I will have that done by next week. I need to also add more information on the structures of the microtubules e.g. the tubulin

--Z3369112 (talk) 15:46, 9 May 2013 (EST) Course coordinator looked through our group page today. Some comments on our page include revisiting Introduction once whole page is complete, referencing must not include review articles if possible, history table information should be distilled to key components and include images or drawings (based on other images) for events, structure section should touch on microtubule, balance of images and text (pretty pictures!), inclusion of student image disclosure, current research is within the last 5 years, select a few proteins to discuss and glossary does not need to include references. Also, before the due date, we should include all the conversations (relevant ones) we had in our FB group. From other groups, course coordinator suggested Public Library of Science website.

--Z3374392 (talk) 15:57, 9 May 2013 (EST) Have a look at Journal of Cell Biology and Public Library of Science. They will have less copyright issues

--Z3369112 (talk) 21:15, 1 May 2013 (EST) Based on what we discussed on our alternate discussion page, we should aim to add on more information than what was previously contributed. Some suggestions could be searching for more relevant articles and if you're unsure, asking another team member for their input. We all have assessments to do that takes up a lot of time, but hopefully we can all help each other out.

--Z3374392 (talk) 17:37, 24 April 2013 (EST) I saw some more useful things in the last lecture regarding structure. I will try to incorporate this new information soon. Btw, we should all be adding more information and making the page look good.

--Z3369112 (talk) 13:11, 18 April 2013 (EST) Problem with this topic is though we have a general idea of what needs to be presented, we don't know if we're going into too much detail about each thing. We could aim to get this Wiki done a few days/weeks prior to the due date and possibly present a draft? Additional note: latest additions to the discussion page should be entered right underneath the conversations/comments heading. That's what the lecturer said :)

--Z3374392 (talk) 19:58, 16 April 2013 (EST) I hope my section on structure isn't too concerned with molecular pathways. I'm worried that I may have left some of the 'major' aspects out.

--Z3369112 (talk) 19:15, 15 April 2013 (EST) I'm doing the Mechanism of Formation section. After discussing with the lecturer, I decided not to focus so much on the molecular pathways involved in the spindle assembly models and instead, just name all the proteins/parts involved in the action. Still have to look up more journal articles on the topic I think, as I feel that my section could still be improved.

--Z3370664 (talk) 16:54, 11 April 2013 (EST) : I'm doing the introduction, historical research, and current research sections.

Transcript of Discussion from Facebook group page

--Z3369112 (talk) 00:01, 16 May 2013 (EST) In order to make communication between each of the members easier, a private group page was formed in Facebook in order to keep members updated in any changes that was made to the group Wiki and also to function as an alternate location for discussion. Below is the transcript of said discussions with names removed.

25th March 2013

Z3374392 hey was the topic 'cell division?' I was thinking perhaps binary fission. How about you guys? any ideas?

Z3369112 Yup, the topic was cell division. I'm alright with that

Z3369112 Just as a note, some of the topics he suggested were: one of the phases, cytokinetics, spindle formation and how organelles segregate (mitochondria, etc.)

Z3376548 hmm..binary fission is prokaryote-specific cell division.. if we choose to talk about it then we might need to go for all the steps instead of just one specific phase like, metaphase ...more a good idea if we focus on one phase perhaps~

Z3369112 True... I just checked the Wiki and Prophase and Anaphase are already taken

Z3374392 I'm kinda liking spindle formation

Z3376548 and I am all good with it, should we put it in ourgroup then? be4 it's taken ?

Z3374392 yes please!

Z3369112 It would be a good one, considering we can have nice labelled diagrams too

Z3376548 done...~

Z3370664 are we doing spindle formation in mitosis? or does it matter if we do both meiosis and mitosis?

Z3374392 I haven't looked into it yet, but I think they use the same processed

Z3374392 processes*

Z3369112 Yeah, its the same process, just called a different name I think

Z3369112 The only sections I can think of to write so far are structure and function

Z3374392 well since it's a wiki page, probably history as well?

Z3374392 and mechanism of formation

Z3370664 and current research

28th March 2013

Z3369112 Task for Easter break: 1) Find four research articles that are relevent to your section and include a brief summary each as to why it is useful (one paragraph). Make sure someone hasn't already chosen the same articles. 2) Find one relevant image/figure that can be used and important for the topic. 3) All should be linked as Lab 3 assessment on your student page too. 3) Update your section sufficiently.

29th March 2013

Z3374392 what did the course coordinator say about using review articles? Because I found a really good one and want to use it D:

Z3369112 He said he prefers research articles BUT if it's a really good review, he'll allow it. Don't think he'll allow that many though.

Z3374392 cool beans i'll just use one then

Z3374392I just realised that there are different types of spindles during the phases e.g. mitotic spindle and central spindle. Should we specifiy that we're doing mitotic spindle?

Z3374392 i found this whole article on just central spindles =S http://www.nature.com.wwwproxy0.library.unsw.edu.au/nrm/journal/v10/n1/full/nrm2609.html#B2

Z3374392 or should we talk about all of it? Although we're still just collecting information. We can narrow it down after we do more research?

Z3369112 Collecting information first would be better.... But yeah, if it starts getting too much, we can just stick to one type of spindle.

3rd April 2013

Z3374392 okay i've uploaded stuff onto the group page! It's not complete or anything, but have a look anyway =)

Z3369112 Good job so far!

Z3374392 i'm so incompetent. took me 30 mins to upload one image!

Z3369112 Haha practise makes perfect! At least you've got pictures up. Each remotely good image I find has some weird copyright issue D:

Z3374392 I KNOW O_O. It actually took me 2 days to find that green spindle picture

4th April 2013

Z3376548 hello group fellows! after spending time on my subsection which is "function of spindle apparatus" , I found nothing more to talk about but just it is there to pull two chromotids apart........

It has more for me to talk about as now I am focusing on the functions of some un-replacable substances that aid spindle formation, as in like, the function they have to stablise spindle anchoring, etc...

I am thinking about placing them in a subsection "current research and past research"... any suggestion?

Z3369112 Sounds good since it is relevant. Not too much for you though?

Z3374392 I still think you should have at least a brief mechanism of their function =O

Z3376548 ok i will do both

Z3374392 i think they also help maintain bipolarity which is important

4th April 2013

Z3374392 can someone please check if i've done this right? http://cellbiology.med.unsw.edu.au/cellbiology/index.php?title=File%3AMitosis_and_spindle_geometry.jpg

Z3369112 Looks about right, but then again, we never received feedback on whether we did it right the first time lol

Z3374392 true that

Z3376548 so.... another question, how current ##should current research usually be? I reckon within 5 years maybe?

Z3374392 yeah, that sounds good

6th April 2013

Z3374392 Yo, who is doing mechanism of formation btw?

Z3369112 That's me

Z3369112 Most of the information I pull up though keeps overlapping somehow with the structure and function so far

Z3374392 that's what i've been finding too D: I found a good review article on it though http://www.sciencedirect.com.wwwproxy0.library.unsw.edu.au/science/article/pii/S0962892400017864. Are you talking about the molecular basis of the formation and destruction of microtubules etc?

Z3369112 I was thinking about that, but course coordinator keeps emphasising that cell biology doesn't focus on the molecular side (molecular biology) so I'm not sure. HELP D:

Z3374392 oohh yeeah D: Perhaps email him? I mean according to him, cell biology is just structure and function. With spindles, there's only so much structure and function you can go into without bringing in molecular mechanisms =S

Z3374392 Also, that's why I think we should definitely still keep 'Function' as one of our subtopics even though they only do one damn thing really LOL

Z3369112 Emailed. Hopefully he replies soon. I feel really bad for not adding anything into the wiki yet ><

Z3374392 He replies pretty quickly usually! Dw about it! everyone knows you're doing stuff

8th April 2013

Z3369112 I've put some of my section up on the wiki (emphasis on 'some' haha). Course coordinator still hasn't replied to my e-mail about the molecular focus yet ><

Z3376548 I have done some in current research part... And I will catch up on the function part soon...

Z3374392 it's cool, we have plenty of time! Just remember to put something up before thursday because that's when the course coordinator will check

Z3370664 i'll also add stuff to my sections today. i've had so many other assessments due this week so i was really preoccupied.

Z3374392 no worries

11th April 2013

Z3370664 I added an article summary in the current research section, along with the image from the article. I'll add more articles next week. I also have a lot of articles to help me write in the historical research section, but so far i just pasted in the summary that i wrote for my 4 articles for the lab 3 assessment. I need more time to organise everything in order and then i need to put them into the table. I can't put them in the table now because i need to organise all the 200 years of history and that's going to take time, so i'm sorry i couldn't add much yet.

24th April 2013

Z3374392 we should be doing more stuff on our page =/ I admit, I haven't touched it in ages!

Z3369112 Yeah, ever since that initial flood of information... Let's make it a point to add on more stuff to it by Sunday, guys? If anything, update the discussion page!

24th April 2013

Z3374392 Z3370664, I was thinking you could slowly start organizing your info nicely on the page? =) Course coordinator will be going through each page on the big screen next week so we should make it look nice. Thanks!

Z3370664 yeah i'll do it this week.

10th May 2013

Z3374392 hey Z3370664, remember to add an epic picture to the intro. Perhaps one of those fluorescence ones? They always look cool. And thumbnail images might look good in the timeline. =D

Z3370664 i have some pictures for the timeline and i uploaded them last week but forgot the codes so i didnt add them inside the table yet. I'll add them soon. And i'll look for some good pictures for the introduction. I was working on another assignment so i didnt get time before. sorry.

10th May 2013

Z3374392 hey you guys, the last reference thing in my structure section just won't work! I don't know what I'm doing wrong. When you get time, can someone please have a look and try to fix it? Thanks! Btw I added some more information on structure

Z3374392 Also, I'm thinking we should add a section on complications/diseases

Z3374392 I'm starting it now

Z3374392 http://jcb.rupress.org.wwwproxy0.library.unsw.edu.au/content/199/7/1025.full.pdf+html

Z3370664 which reference isnt working? i'm confused. Do you mean the external link to the library? can u paste the name of the article so i can find it?

Z3374392 dw i fixed it! i was being really dumb LOL

Z3374392 thanks though!

Z3370664 but that external link isnt working.

Z3374392 the one i've posted in these comments?

Z3370664 no the one in the structure section when i clicked from the wiki page

Z3374392 OOH really? dammit, let me have a look

Z3374392 this is what i'm trying to link http://pubs.rsc.org.wwwproxy0.library.unsw.edu.au/en/Content/ArticleLanding/2004/OB/b403634d you have to be logged into to unsw library though. Do you know how to fix it?

Z3370664 here is the pubmed page for your article: http://www.ncbi.nlm.nih.gov/pubmed/23266953 Mitotic spindle (DIS)orientation and DISease: ca... [J Cell Biol. 2012] - PubMed - NCBI www.ncbi.nlm.nih.gov

Z3370664 and here's the correct direct link to the full article: http://jcb.rupress.org/content/199/7/1025.long

Z3374392 see if the link works now

Z3370664 it wasnt working so i fixed it now.

Z3374392 thank you!

15th May 2013

Z3374392 in Mechanism of formation, I think we'll need to mention dynamic instability in a bit more detail

Z3369112 Noted!


The following articles are related to the structure the spindle apparatus:

Article 1: As reviewed in Glotzer (2009), the spindle apparatus is made from a combination of microtubules, motors and microtubule associated proteins (MAPs). [1] This review article is mainly concerned with the central spindle that coordinates cytokinesis. Microtubules that make up spindles are cylindrical polymers that are assembled from dimers of alpha-tubulin and beta-tubulin. They are polar filaments that have a fast-growing plus end and a slow-growing minus end that is often capped by the gamma-tubulin ring complex, a ring-shaped microtubule nucleator. During metaphase, the mitotic spindle is comprised of kinetochore fibres, astral microtubules and interpolar microtubules. The fusiform shape of the spindle is the result of the microtubule minus ends focusing at the poles and by cross-linking interpolar microtubules in an overlapping region situated in the midzone. At the beginning of anaphase, the kinetchore fibres shorten ( delivering sister chromatids to the poles) and astral microtubules elongate. The region between the two poles is called the spindle midzone and the microtubules that populate this region are called midzone microtubules. The term central spindle refers to the structure at the centre of the midzone, where the plus ends of the microtubules interdigitate. The microtubules of the central spindle eventually lose their interaction with the spindle poles. As the formation of the cleavage furrow progresses, the central spindle becomes compacted dense structure known as a the midbody.

Article 2: In the spindle, kinetochore microtubules have their plus ends embedded in the kinetochores of the sister chromatids and their minus ends at the spindle pole. This study shows that kinesins are important to maintain spindle bipolarity. [2] The simulataneous KinI induced disassembly at both the plus and minus ends may result in the poleward driving forces. Upon disassembly, chromosome associated kinetochore microtubules are driven back to their poles. Centromere-associated KinI proteins act to disassemble the plus end, causing the spindles to shorten during anaphase.

Article 3: In most animal cells microtubules are nucleated at the centrosomes found at the spindle poles. However, it has been observed that spindles can still form in cells lacking centrosomes. The results show that non-centrosomal microtubules contribute to to spindle formation even in cells with centrosomes. These cells expressed GFP-alpha-tubulin. It was also found that the centrosomal microtubule array can be composed of both nucleated and peripheral microtubules. Peripheral bundles were able to move laterally in order to form the spindles between the spindle poles. [3]

Article 4: For sister chromatids to be correctly segragated between daughter cells, the kinetochore forms bivalent attachments with the spindle microtubules and the kinteochores position themselves correctly with respect to the division plane of the cell. Bivalent attachment of the sister chromatids to the spindle is achieved when the plus ends of the microtubules emanating from each pole interacts with the kinetochores of each sister pair and then becomes embedded. It is well established that CLIP-170/Tip1 localizes to the kinetochore.The plus-end microtubule binding proteins ( +TIP) play a significant role in the regulation of microtubule stability and cell polarity during interphase. In this study, they investigated the role of +TIP proteins during mitotic progression and provide evidence suggesting that the +TIP protein Tip1 affects directly or indirectly the movement of the chromosomes towards to the poles during anaphase [4] .


References

  1. <pubmed>19197328</pubmed>
  2. <pubmed>14681690</pubmed>
  3. <pubmed>14588246</pubmed>
  4. <pubmed>20498706</pubmed>


Note: there may be some overlap between the structure and function subtopics. We'll have to discuss further about this.




The following articles are related to the functions of several components that contribute to spindle formation:

Article 1: This article searches the roles of actin filaments (F-actin) and F-actin-based motors (myosins) which are required components of mitotic spindles. In their research, they found out that myosin-10 (Myo10) is important for assembly of meiotic spindles. In more detail, Myo10 set themselves to mitotic spindle poles and is very important for proper spindle anchoring, normal spindle length, spindle pole integrity as well as progression through metaphase. They also found out the antagonistic relationship between F-actin and Myo10 in maintenance of spindle length and that they work independently.[1] Actin filaments (F-actin) and F-actin-based motors (myosins) are essential components in the proper functioning of spindle apparatus. They are required for correct positioning of the spindle towards the anchor point.


Article 2: Their finding found out the function of the long-tailed class-1 myosin myosin-1C from Dictyostelium discoideum during mitosis. They use the data obtained as back up, suggested that myosin-1C binds to microtubules and play parts in maintenance of spindle stability during chromosome separation and that the association of myosin-1C with microtubules is mediated through the tail domain. Further data has leaded to another suggestion that myosin-1C tail can inhibit kinesin motor activity, strengthen the stability of microtubules as well as forming crosslinks between microtubules and F-actin. [2] Myosin-1C motor and tail-domain-mediated MT-F-actin are required for the relocalization of certain protein from the cell periphery to the spindle. Therefore, both contribute to the formation and stability of spindle apparatus in considerable amount.

Article 3: This article states thoroughly for the process of spindle assembly, spindle positioning and separation of the nascent spindle poles in relation to cortical dynein-based pulling on astral microtubules, and kinesin-based sliding of polar microtubules. They talked about the motors and microtubule binding proteins at kinetochores which provide attachment sites for microtubule to the chromosomes. They also states that there is a complicated mechanism that which perform pushing and pulling action to chromosomes that puts them in metaphase plate position. Kinetochore motors and microtubule binding proteins can also give signal to the cell cycle regulatory machinery for on time advance passing the cell cycle phrases. [3] Dynein-based pulling and kinesin-based sliding of microtubules is very important in spindle assembly and positioning. Motors and microtubule binding proteins will aid spindle for its function to separate sister chromatids.


Article 4: By combine the use of force-calibrated needles, high-resolution microscopy, and biochemical perturbations, the researcher analyze the vertebrate metaphase spindle and found that spindle viscosity is dependent on microtubule density and cross-linking. Spindle elasticity are said to be relating to kinetochore and non-kinetochore microtubule rigidity, and also to spindle pole organization by kinesin-5 and dynein. [4] The data obtain in their research provides micromechanics modal insight of this cytoskeletal architecture and provide insight into how structural and functional stability is maintained for proper control of spindle function.


References

  1. <pubmed>18606852</pubmed>
  2. <pubmed>21712373</pubmed>
  3. <pubmed>21920311</pubmed>
  4. <pubmed>21703450</pubmed>





4 Research Articles For Historical Research on Spindle apparatus from z3370664:

Article # 1:

<pubmed>6885908</pubmed>

In this article[1], the author researched the measurements of force produced by spindles during anaphase of mitosis. A glass needle was used to measure the force that each spindle acts on each single moving chromosome. The use of the needle resulted in producing a force on the chromosome in opposition to the force produced by the spindle, and this was measured using the deflection of the needle tip. Twelve experiments were performed on grasshopper spermatocytes (which was chosen because the research ensured the surface of the cell did not interfere with the contents inside the cell). The results showed the relationship between the velocity of chromosomes and the opposing forces of the spindles. It was found that the spindles produce a large force, which shows that it can affect the stability and length of microtubules. This article is relevant in the spindle historical research section.


Article # 2:

<pubmed>5076360</pubmed>

This article [2] discusses research in the topic of centrioles and their role in spindle apparatus formation. Centrioles are normally present in animal cells. Spindle apparatus originate from a 'center' which is called the centriole. It helps organise the spindles to originate from a single point. However centrioles are absent in many plant cells. Ovaries of rate, mice, hamster, Mongolian gerbils, and humans were used in this study. Oocyte samples were taken out of the ovaries, and examined. The results showed that centrioles were present in human oogonia, as well as the neonatal ovaries of rats. However, centrioles seem to be absent in later stages of oogenesis. It was not discovered what exactly happens to the centrioles, because there was no observation of breaking down. The results also show that an intact centriole is not needed for successful completion of meiosis. Mitotic spindles in early mouse embryos and many plants lack centrioles. This article will be helpful in the historical research section.


Article # 3:

<pubmed>4734864</pubmed>


This article [3] researches mitotic spindle thermodynamics and equilibrium during metaphase. Sea urchin eggs undergoing metaphase were used in this study. These eggs were observed using polarization microscopy. Spindle fibres were said to be 'labile' in nature, however the existence of spindle fibres were not confirmed until 1953 by Inoue, who was able to show their existence in living cells, using polarization microscopy. He also discovered that hypothermic treatment, as well as the antimitotic drug colchicine can abolish these spindle fibers. The author of this article investigated the equilibrium of spindle fibres that are dependent on temperature. Rise of temperature seems to cause an increase in birefringence. Birefringence is also related to the proportion of tubulin content of microtubules. This article is useful for the historical research section.



Article # 4:

<pubmed>9227856</pubmed>


This article [4] researches the effect of intracellular pH on mitotic spindle apparatus. Fertilized eggs of Scaphechinus mirabilis and Clypeaster japonicus were used in this study. The pH of Scaphechinus mirabilis was 7.34, while the pH of Clypeaster japonicus was 7.31. The pH of both these egg species changed after their nucleus was broken down with the treatment of adding sea water which contained ammonia or acetate which had pH of variable values. The results showed that the mitotic spindles increased to their maximum size at pHi 6.70. However, the spindle length then decreased when the pHi was changed from 6.70 to 7.84. The increase in spindle size was found to also be related to the amount of microtubules present. Inhibition of the mitotic spindle organisation were observed at pHi 6.30. Most of the eggs of Scaphechinus mirabilis arrested at the metaphase stage when the pHi was 6.70. The main result found overall from this research was that a slightly acidic pH results in the stabilization of microtubules in the spindles, and the number of microtubules present were larger than it is in normal eggs. This article is useful for the historical research section.




References

  1. <pubmed>6885908</pubmed>
  2. <pubmed>5076360</pubmed>
  3. <pubmed>4734864</pubmed>
  4. <pubmed>9227856</pubmed>




Four Research Articles on Spindle Apparatus: Mechanism of Formation from z3369112

Mechanisms of mitotic spindle assembly and function

This journal (although a review) is a comprehensive source for information on the observations that led to the current models of spindle assembly as well as recent discoveries in the field. Since the section of Mechanism of Formation requires information on the two spindle assembly models (Search and Capture & Microtubule Self-Organisation), it was deemed appropriate. This review centers entirely on the spindle assembly models.[1]

Maize meiotic spindles assemble around chromatin and do not require paired chromosomes

This research article provides a good explanation on how the Microtubule Self-Organisation or Self-Assembly model works. The scientists in this study propose a model for spindle formation in maize meiocytes where microtubules firstly appear around the chromosomes during prometaphase and aids the microtubules to self-organise. The scientists studied the organization of microtubule arrays in wild-type maize meiocytes and three maize meiotic mutants, desynaptic1 (dsy1), desynaptic2 (dsy2) and absence of first division (afd). It also references the Search and Capture model.[2]

Mitotic spindle poles are organised by structural and motor proteins in addition to centrosomes

This study provides results that show that the microtubule micro ends are directed to the spindle poles through mechanisms involving contributions from both centrosomes and microtubule motor proteins. All the observations done in their experiment with Xenopus eggs is discussed in the context of the Search and Capture model, which was useful to the section. The scientists in this article who that a certain antibody disrupts the organisation of microtubule minus ends and localisation of the nuclear mitotic apparatus protein at spindle poles.[3]

The chromosomal passenger complex is required for chromatin-inducted microtubule stabilization and spindle assembly

In relation to the Microtubule Self-Organisation model, it discusses the molecular pathway cascade of Ran-GTP. This assessment does not need to go into as much detail as the study explains, but for the general overview, it was proven useful. In particular, the Introduction section does a good job at explaining its function. Whilst it goes rather indepth into the topic (more than required for Cell Biology), it discuses the complexes required for chromatin-induced microtubule stabilisation and spindle formation (Microtubule Self-Organisation model).[4]

Useful Image to be used for Spindle Apparatus: Mechanism of Formation

Search and Capture spindle assembly model

References

  1. <pubmed>18275887</pubmed>
  2. <pubmed>9811565</pubmed>
  3. <pubmed>9281583</pubmed>
  4. <pubmed>15260989</pubmed>