Difference between revisions of "Talk:2013 Group 4 Project"

From CellBiology
Line 3: Line 3:
  
 
===Conversations/Comments from Group Members===
 
===Conversations/Comments from Group Members===
 +
 +
--[[User:Z3376548|Z3376548]] ([[User talk: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!
 +
 +
--[[User:Z3376548|Z3376548]] ([[User talk:Z3376548|talk]]) 20:36, 15 May 2013 (EST)I am thinking about placing them in a subsection "current research and past research"...
 +
 +
--[[User:Z3376548|Z3376548]] ([[User talk: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...
 +
 +
--[[User:Z3376548|Z3376548]] ([[User talk: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........
 +
  
 
--[[User:Z3369112|Z3369112]] ([[User talk: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.
 
--[[User:Z3369112|Z3369112]] ([[User talk: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.

Revision as of 20:37, 15 May 2013

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.


Conversations/Comments from Group Members

--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........


--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.

--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 :)

--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.

--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.

--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.

--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

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




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>