cell biology course

Question

Why does it take up to a full cell cycle to observe the effects of a temperature-sensitive mutation? 

This is regarding to yeast strains (cdc13-1) in the CDC13 gene have temperature sensitive mutation where they grow fine at 23C but they experience G2 cell cycle arrest at 37C. and yeast cells take 60-90 minutes to go through 1 full cell cycle. so why does it take a full cell cycle to see those effects from temp mutations?

I need explanation ASAP pleaseee!

Answer 1

In a temperature-sensitive mutation, the mutant protein fails to function at high temps but functions enough to allow cell division at lower temperatures. All biological process require the optimal environmental conditions for giving best results and even slight changes affect the efficiency of biological process. In budding yeasts, a uniform cell-cycle arrest can be detected by just looking at the cells- you'll be able to indicate the point in the cycle at which the mutant is arrested. The mutation lies in the gene which encodes for protein but the effect is seen in the binding of RNA polymerase 2 to DNA. The temperature sensitive phenotype could be expressed during a specific developmental stage to study the effects, and this mutant is only apparent only at high temperatures.

Hope this helps!! :)