So, I did a sister chromatid exchange and cromosomal aberrations assay in order to evaluate the genotoxicity of a drug .
the metaphase chromosomes were in a zigzag shape , so I wonder is it normal ?
Hello...
I've also been doing metaphase spread during my PhD. I was looking at the architecture of chromosomes. Usually, the loss of "proper" architecture shows defects in proteins such as SMC.
How do your controls look like? Do they also exhibit a bent shape? In which case, it just could be due to experimental conditions, such as synchronizing agent, how many days the samples have been kept and so on...
I have few references on the SMCs if you interested in, they show how chromosome architecture can be altered in response to SMCs silencing.
Please clarify what you mean by zig zag pattern?
Is it the checkerboard pattern observed in Bloom syndrome?
If yes, the drug you used may have a genotoxic effect; So, comparing the culture with this drug to a similar culture without drug (as negative control) is necessary.
Our work about exposure to several genotoxic factors showed a significant elevation of sce but still lower to the rate observed in Bloom syndrome. So, if the pattern you observed is like checkerboard, the drug you used should have a genotoxic effect through helicases path-way!
Baxter, J., & Aragón, L. (2012). A model for chromosome condensation based on the interplay between condensin and topoisomerase II. Trends in Genetics : TIG, 28(3), 110–117. http://doi.org/10.1016/j.tig.2011.11.004
Bazile, F., St-Pierre, J., & D'Amours, D. (2010). Three-step model for condensin activation during mitotic chromosome condensation. Cell Cycle (Georgetown, Tex.), 9(16), 3243–3255. http://doi.org/10.4161/cc.9.16.12620
Green, L. C., Kalitsis, P., Chang, T. M., Cipetic, M., Kim, J. H., Marshall, O., et al. (2012). Contrasting roles of condensin I and condensin II in mitotic chromosome formation. Journal of Cell Science, 125(Pt 6), 1591–1604. http://doi.org/10.1242/jcs.097790
Hudson, D. F., Vagnarelli, P., Gassmann, R., & Earnshaw, W. C. (2003). Condensin is required for nonhistone protein assembly and structural integrity of vertebrate mitotic chromosomes. Developmental Cell, 5(2), 323–336. http://doi.org/10.1016/S1534-5807(03)00199-0
Ono, T., Fang, Y., Spector, D. L., & Hirano, T. (2004). Spatial and temporal regulation of Condensins I and II in mitotic chromosome assembly in human cells. Molecular Biology of the Cell, 15(7), 3296–3308. http://doi.org/10.1091/mbc.E04-03-0242
Ono, T., Ono, T., Losada, A., Losada, A., Hirano, M., Hirano, M., et al. (2003). Differential contributions of condensin I and condensin II to mitotic chromosome architecture in vertebrate cells. Cell, 115(1), 109–121. http://doi.org/10.1016/S0092-8674(03)00724-4
@Haya Abu-Khadra
These are few references that maybe can help you. From memory, in Green, and Ono publications, there's a description of chromosomes you described.
Hope it will help you, or at the very least guide you.
Dear Abu-Khadra,
Actually, if you upload an example picture of metaphase, It can be more understandable for zigzag shape.
As said Halil Erhan Eroğlu, I think that : "A picture is worth a thousand words"
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