- 1 Anaphase
- 1.1 Introduction
- 1.2 History
- 1.3 Anaphase
- 1.4 Anaphase in Meiosis
- 1.5 Anaphase in Mitosis
- 1.6 Defects resulting from Anaphase malformation
- 1.7 Current research
- 1.8 Suggested research
- 1.9 Glossary
- 1.10 References
- Chromosomes split
- sister chromatids move to poles at opposite ends of cell
- Around 1% of cell cycle duration?
- starts with Metaphase to Anaphase transition
- commences with Anaphase promoting complex which marks inhibitory chaperone Securin - Securin inhibits separase
- Importance of Anaphase in living replicating organisms
|1871||Alexander Kowalevski was the first to comprehend and then figure out the achromatic spindle.|
|1879||Walter Flemming discovered the longitudinal splitting of chromosomes when in mitosis.|
|1925||Edmund Beecher Wilson published a timeless work in a book titled "The Cell in Development and Heredity". This book compares the different stages of the cell mitotic cycle and identifies this division process within different organisms. |
|1943||Hans Ris Uniquely used live imaging as opposed to photographs and identified two stages in anaphase firstly the shinking as the chromosomes approach the poles and then the elongating as they move further apart.|
Metaphase to Anaphase transition
Metaphase-to-anaphase transition is tightly controlled by anaphase-promoting complex (APC) motions. APC promotes the degradation of several proteins that inhibit anaphase. The regulatory protein Cdc20 triggers APC/C at the start of the metaphase-anaphase transition. Cdh1 a membrane protein which is able to control the fate of certain cells, triggers anaphase through the G1 stage of the cell cycle. APC/C specifically targets securin(anaphase inhibitor), Early destruction of this inhibitor is coordinated by nuclear transport factors(Nup98 and Rae1), This mechanism is strictly governed to guarantee appropriate timing of degradation. 
Mistakes during this process can cause segregation issues leading to the possible demise of the organism. 
Process of sister chromatid separation
PMID: 10403247 - Sister-chromatid separation at anaphase onset is promoted by cleavage of the cohesin subunit Scc1.
PMID: 22580470 - Sororin is a master regulator of sister chromatid cohesion and separation.
PMID: 14681690 - Two mitotic kinesins cooperate to drive sister chromatid separation during anaphase.
PMID: 9335333 - Cohesins: chromosomal proteins that prevent premature separation of sister chromatids.
Spindle apparatus and Kinetochore
Spindle fibers in meiosis are known as the meiotic spindle fibers. Spindle fibers are predominantly made up of microtubules, which are mediated by kinetochore. Kinetochore is a complex protein structure that can be found in the chromosomes that link the chromosomes to the spindle microtubules. 
Microtubules can be divided into two categories. Microtubules that interact directly with the kinetochores are known as the kinetochore microtubules (kMTs), whereas microtubules that do not interact with the kinetochores directly, instead they interact with the chromosome arm and other microtubules are known as the non-kinetochore microtubules (non-kMTs). In meiosis, the spindle apparatus are mainly made up of non-kinetochore microtubules. The functions of non-kMTs in meiotic spindles are to maintain a stable chromosome positioning, and to form a proper spindle size. Non-kMTs also play a role in the normal dynamics of kMTs. 
The construction of the bipolar spindle involves complex organization of the polymerization dynamics & arrangement of microtubules.
Meiotic spindles need kinesin-5 for the separation of the spindle poles. Inhibition of kinesin-5 after spindle fiber formation causes the structure to collapse. Hence, kinesin-5 is needed in order to maintain the bipolarity of the meiotic spindles. 
Spindle checkpoint ensures correct kinetochore-microtubule arrangement and attachment, anaphase cannot proceed until all chromosomes are aligned correctly in a bipolar fashion.
Anaphase to Telophase
Essentially the transition from Anaphase to telophase can take 2 pathways, the conventional or normal pathway involves the co-ordination of Kinetochore and microtubules attachment with the strict dictation from the spindle assembly checkpoint (SAC) where as the other route is basically a "short cut" by passing this checkpoint through a process known as mitotic slippage. The kinetochore is a specific zone located on the chromosomes centromeres.  During Anaphase chromatids are pulled apart by the microtubules attached to the kinetochore in the direction of the opposite poles. The organisation of these microtubules is critical for regulation of this phase.  Anaphase is defined by the the chromatids separating to become a daughter chromosomes.  The SAC is solely responsible for the inhibition of telophase initiation. This checkpoint acts as a government arresting cell processes if there is inadequate supply of kinetochore-microtubule attachments. It should be noted that there are cellular processes that can override and bypass this government through mitotic slippage allowing anaphase lateral entry into telophase. 
Anaphase in Meiosis
1/ Stages of anaphase in meiosis - then go into depth about proteins and their effect
PMID: 12737807 - Division of the nucleolus and its release of CDC14 during anaphase of meiosis I depends on separase, SPO12, and SLK19.
PMID: 10440376 - Cohesin Rec8 is required for reductional chromosome segregation at meiosis
PMID: 12714746 - Requirement of Cks2 for the first metaphase/anaphase transition of mammalian meiosis
Anaphase in Mitosis
PMID: 12049731 - The anaphase-promoting complex: proteolysis in mitosis and beyond.
PMID: 16287863 - Anaphase-promoting complex/cyclosome controls the stability of TPX2 during mitotic exit.
Defects resulting from Anaphase malformation
- If the chromosome tips are damaged during anaphase then cytokinesis cannot occur and therefore the cell cannot divide into two daughter cells, not sure if this is in relation to both mitosis and meiosis but should be interesting to further research. The experimental removal of chromosomal tips shows cell division being delayed, the furrow itself being delayed or even regressing from its ready to divide state.
- Anaphase-Promoting-Complex mutants of C. elegans demonstrate defects in germline proliferation, the development of the female vulva and male tail and the metaphase to anaphase transition in meiosis I. Therefore irregularities in the APC contribute to physical deformities in this species.
- The Anaphase-Promoting-Complex has many important roles in the development, function and survival of the nervous system. Incorrect ACP activity leads to some neurological and psychiatric disorders. Research into the APC's role in neurobiology may grant us ways to use the APC to manage neurological disorders such as mental retardation and autism to even neurodegenerative disorders.
- When the chromosomes do not separate properly in Anaphase, referred to as "nondisjunction" aneuploidy results. This refers to an abnormal number of chromosomes. A well known one is Trisomy 21 or Down's syndrome in which there are three copies of the 21st chromosome. Others include Patau syndrome, Edward's syndrome, Klinefelter syndrome and Turner's syndrome NO REFERENCES AT END OF SENTENCE!!! FIX THIS AND OTHERS IN EDITING!!!
- Anaphase bridges can cause mutations such as the structural rearrangement of chromosomes which usually lead to the formation of isochromosomes (chromosomes which, after losing one of their arms are replaced with a copy of another arm) and whole-arm translocations, the loss of the entire chromosome through mitotic spindle detachment or faulty cytokinesis in which the failure to divide results in polyploidy (more than 2 copies of a chromosome) and additional centrosomes which may lead to multipolar spindle formations in future mitosis. The presence of chromatin bridges in Anaphase is also linked to chromosomal instability156327</pubmed></ref> to cancer.
- PMID: 11832245 - The anaphase-promoting complex and separin are required for embryonic anterior-posterior axis formation*****
Metaphase to Anaphase (mat) Transition–Defective Mutants in Caenorhabditis elegans
The 'anaphase problem': how to disable the mitotic checkpoint when sisters split.
PMID: 23566798 - this is copyrighted, can we still use copyrighted journals as long as we reference like normal and don't plagiarise anything? Or steal images? [Mark said we can draw our own versions but mention we based them off copyrighted images/ideas for instance]
- 2008: 
- 2010: 
The anaphase catastrophe as a possible targeting system for tumor cells
The Anaphase Catastrophe is a programmed cellular death mechanism (apoptotic) that targets tumour cells that have more than two centrosomes. Tumor cells are able to live with their abnormal number of centrosomes due to a clustering of their centrosomes thanks to special pathways, which allow them to keep the bipolar chromosome segregation seen in normal division. These abnormal cells can then proceed to anaphase with their multipolar spindles and segregate their chromosomes to an unusual number of daughter cells *more than two). All resulting daughter cells will subsequently die, hence this is what is known as anaphase catastrophe. Because it is an intrinsic targeting system for tumor cells, it has been suggested that it may be a target for cancer therapy and warrants further future research.
- Figure 2 image from ^ paper is a good image to use for this section, I'm pretty sure it's free but could someone just confirm this with me as I don't want to infringe any copyrights
It has been known for quite some time that due to the extension of the anaphase spindle, spherical tissue cultured cells will elongate to a capsular shape while preparing for cytokinesis. A study has based itself on further understanding the process of anaphase cell elongation, however it is noted that the functions of equatorial contraction, polar relaxation, and the spindle pushing force remain unknown. Whether cell elongation is a phase in its own right or part of another, and how these cellular processes are controlled are not understood.
APC structure & purpose of mitotic phosphorylation
So far, there have not been any successful vertebrate Anaphase Promoting Complex/Cyclosome (APC/C) reconstitutions from recombinant subunits in vitro and thus the purpose of the multiple mitotic phosphorylations it undergoes as well as what kinases are involved remains a target for study. Current study is therefore limited to APC phosphorylation in vitro in comparison with APC modification in vivo, advances have however been made in the effects of regulation via phosphorylation of CDC20, which is a protein complex associated with the APC which serves to activate it.
Correct division of cellular contents between two daughter cells depends upon spatial and temporal cues, anaphases' microtubular system organizes itself at the spindle midzone and functions to orient the cell division plane in the center of the segregating chromosomes. The signalling pathway responsible for this is not understood, but this molecular study explores how the phosphorylation of Aurora B kinase; a regulator of mitosis, ultimately leads to a gradient which centers at the spindle midzone. The study is therefore successful in the discovery of a possible regulatory mechanism for the anaphase phosphorylation gradient, and suggests that its findings may be useful in the future development of a model for anaphases' spatial patterning.
- Research conducted on Saccaromyces cerevisiae has shown that it is damage induced to the DNA, and not the...
- Current research is from the last 5 years, anything older -> in history
- Anaphase Promoting Complex/ Cyclosome (APC/C) - A large protein complex of multiple subunits which activates during cell division and whose purpose it is to signal for anaphase to begin.
- Cell Cycle - The series of events that occur within a cell during its lifetime; divided into phases of growth, replication and division into daughter cells.
- Chromatids - jkasjdklas
- Chromosome centromere - jkahsdkhas
- Cytokinesis - The final stage of cell division in both meiosis and mitosis, wherein the cytoplasm is constricted so that the products of cellular division (the daughter cells) may separate.
- Kinetochores - kjasdkjas
- Microtubule - kjahsdkas
- <pubmed> 9268050</pubmed>
- <pubmed> 10973989</pubmed>
- Dr Mark Hill 2013, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G