English to Russian Medical Genetics

Transition between the phases is governed by activation of protein kinases (cyclin-dependent kinase (CDK) family) mediated by their cyclin partners. A cell cycle inhibitory protein, retinoblastoma (pRB), is progressively phosphorylated and inactivated by cyclins in the G1 phase of the cell cycle leading to the transcriptional activation of genes required for S phase and DNA synthesis by the E2F family of transcription factors. CDK activity is kept in check by two families of CDK inhibitory proteins (CKIs): the p21 family and the p16 family.