Question

What two stages of the cell cycle is the protein Cdt1 now known to participate in and what role does it play in each?

What is the end result if Cdt1 function is blocked?

Explain how Cdt1, the protein Hec1, and kinetochores all interact.  

Answer 1

In the early stage of cell cycle i.e. G₁ phase, the protein Cdt1 forms hexameric protein complex with the help of Cdc6 protein. This hexameric protein complex prevent the replication of DNA in G₁ phase. Thus, in G₁ phase, cdt1 protein works against the replication.

In S phase of cell cycle, this cdt1 protein is used to prevent the re- replication of DNA by forming the same hexameric protein complex.

If cdt1 function is blocked, no cell cycle is performed because of no control of replication of genetic material.

Hec1 protein is used for the attachment of spindle microtubules to the kinatochores during cell division and helps in segregation of chromosomes.