Mouse embryos that lack the genes encoding Cdks 2 3 4 and 6

Mouse embryos that lack the genes encoding Cdks 2, 3, 4 and 6, four cell-cycle Cdks, are capable of developing to a stage with fully-formed organs, although the animal does not survive to birth. Which of the following statements based on these results is true of these cells? Cells taken from such embryos are capable of proliferating in culture, although more slowly than normal cells. Even though Cdks 2, 3, 4 and 6 are normally expressed at specific times during the mammalian cell cycle, Cdkl is able to cover for their absence. Cdk1 is the only Cdk required to drive a mammalian cell through all of the stages of the cell cycle. All of these answers are correct.

Solution

Answer : D : All of these answers are correct.

Cdk 2, 3, 4 and 6 are involved in G1 (first gap phase) phase of the cell cycle. G1 is the prepartory phase for the synthesis, S phase of the cell cycle.

Cdk1 is involved in M or mitotic phase of the cell cycle but Cdk1 along with cyclin A2 and B1 can drive the cell cycle.