Why fetal cells continue to divide but terminally differentiated adult cells do not divide -
A cyclin-dependent kinase inhibitor protein is a protein which inhibits cyclin-dependent kinase. Several function as tumor suppressor genes. Cell cycle progression is negatively controlled by cyclin-dependent kinases inhibitors (called CDIs, CKIs or CDKIs). CDIs are involved in cell cycle arrest at the G1 phase.
General pathology
There are many cyclin inhibitors which prevent cell to enter into S phase in adult
Phosphatase absent in fetal cells
Proteinase is absent in fetus
Absence of CD kinase
There are many cyclin inhibitors which prevent cell to enter into S phase in adult