Unusual cell division- Identifying mutant protein and genes

[Bex23]

Hi,

I have a hypothetical situation where a mutation has arisen in a mammalian cell culture causing the production of giant multinucleate cells. It seems most likely that the problem is a result of a mutation in the cytoskeleton but since a number of proteins could have caused this mutation how do I narrow it down? And once you have identified what protein has been mutated how would you identify the gene?

The second part of the hypothetical situation is that once the mutant line has been isolated after a period of time mononucleate cells begin to appears. I've been racking my brain but I can't think of a possible explanation, can anyone help?!

[dharavsolanki]

Let's try and discuss this problem. I find this interesting, but ain't no expert.

I'll tell you what I know. The only instance of multinucleate cells I can think of are fusion cells - which were used to study the cell cycle. Which also reminds me that it is possible the multi nuclei cells might just as well be a reuslt of improper cell division - that is, the cells replicate their DNA, divide the nucleus and get ready for the final phase and divide into two separate daughter cells.

So my thoughts were : it was a result of the final phase of cell division going wrong. I looked up Cell division on wikipedia and I got the following. (See quote, and highlights)

This leads me to think the proteins that were mutated were involved with Cytokinesis. It also mentions the role of golgi apparatus in the cell, which makes me think that those would be invovled. Go through it, tell me what you think and we'll proceed.

Telophase
Main article: Telophase

Telophase (from the Greek τελος meaning "end") is a reversal of prophase and prometaphase events. It "cleans up" the after effects of mitosis. At telophase, the nonkinetochore microtubules continue to lengthen, elongating the cell even more. Corresponding sister chromosomes attach at opposite ends of the cell. A new nuclear envelope, using fragments of the parent cell's nuclear membrane, forms around each set of separated sister chromosomes. Both sets of chromosomes, now surrounded by new nuclei, unfold back into chromatin. Mitosis is complete, but cell division is not yet complete.
[edit] Cytokinesis
Main article: Cytokinesis

Cytokinesis is often mistakenly thought to be the final part of telophase; however, cytokinesis is a separate process that begins at the same time as telophase. Cytokinesis is technically not even a phase of mitosis, but rather a separate process, necessary for completing cell division. In animal cells, a cleavage furrow (pinch) containing a contractile ring develops where the metaphase plate used to be, pinching off the separated nuclei.[17] In both animal and plant cells, cell division is also driven by vesicles derived from the Golgi apparatus, which move along microtubules to the middle of the cell.[18] In plants this structure coalesces into a cell plate at the center of the phragmoplast and develops into a cell wall, separating the two nuclei. The phragmoplast is a microtubule structure typical for higher plants, whereas some green algae use a phycoplast microtubule array during cytokinesis.[19] Each daughter cell has a complete copy of the genome of its parent cell. The end of cytokinesis marks the end of the M-phase.

[dharavsolanki]

I guess you didn't want more possibilities but a way to narrow things down. I'm clueless, but I got a feeling for narrowing down - you need more data about the situation. Either that, or documented information about the things that you already know!

I'm saying this because you mentioned cytoskeleton and the wiki article also mentions microtubules in Cytokinesis, which makes me think you kind of made it already!

[Bex23]

Yeah, I was thinking of cytokinesis as well although I didn't realise the golgi apparatus was involved so thanks for that info.

I was thinking of using some kind of microscopy to visualise the mitotic phase so I could see exactly where the cell was arresting. As since cytokinesis consists of more than one stage it would help narrow down the possible protein or proteins that have been affected. Can you think of any other possible test I could do to narrow down the mutated protein/proteins?

Also, aside from sequencing the whole cell genome and comparing it to a normal cell I'm not sure how I would specifically find the protein and subsequently the gene that is involved.

[dharavsolanki]

Hey sorry, forgot about this post altogether! Will get back to this. In the meanwhile, please give me a reply if it worked!