Question

Ch 12: Cell Cycle

A mutation tissue culture can't perform mitosis correctly, but you are not sure exactly what the mutation is. Design an experiment based around idea concerning an issue with cytoskeleton. Then, assume your hypothesis was not supported and come up with a second hypothesis based around an issue with a cell cycle checkpoint.

Answer 1

The cytoskeleton are responsible for the contraction, motility of cells and also helps in the movement of organelles and vesicles in the cytoplasm. In the process of cytokinesis (cell cycle), cytoskeleton plays role in formation of cell polarity, and the functions which are responsible for cellular homeostasis and survival. In the microtubule cytoskeleton interphase cell progression is not certain and can leads to G1 arrest and proportion of cell populations shows the existence of a “microtubule damage, or “post-mitotic” checkpoint in G1 or G2. According to the studies it has been said that the normal cells such as hTERT RPE1 and primary fibroblasts are continuously exposed to certain type of chemicals such as nocodazole , by which mitosis process slips out and arrest in G1 phase. In the anaphase-telophase phase cells completely disassemble microtubules with the pulse of cold and by use of continuous nocodazole or Colcemid treatment which ensures that the cells enter G1 without microtubule cytoskeleton. In the absence of microtubules, cells progress from anaphase to mitosis process with normal kinetics. Same results are being observed for cells in which the microtubule cytoskeleton is partially slows down by low concentration of nocodazole doses. Thus, after a mitosis of normal duration, the integrity of the microtubule cytoskeleton does not allow to checkpoint surveillance or it is not required for the normal cell to progress through G1 and remainder of interphase phase.