Cohesins and Codesins

Chromatin organization changes dramatically during the cell cycle. During interphase (G۱, S and G۲phases), a large part of the chromatin remains loose and non-condensed (euchromatin), and the otherpart appears in a condensated state (heterochromatin). There are chromatin regions that can alternatebetween condensed and non-condensed states during the normal behavior of the cell. Many genes haveto be expressed during interphase, and they need to be accessible to RNA polymerases andtranscription factors, which is easier in a less condensated state of the chromatin. However, duringmitosis (M phase), chromatin achieves a highly degree of compaction and organization to formchromosomes. Segregation of chromosomes between the two daughter cells is a very importantprocess during cell division. The condensation of chromatin to form chromomas is consequence ofhistone modifications. In addition, a group of proteins known as SMC (structural maintenancechromosome) are involved in this compaction mechanism. Cohesins and condensins are SMCproteins.

کلیدواژه ها:

cohesin ، codesin ، metaphase ، prometaphase ، anaphase