Restriction Point
There is a "restriction point" present at the end of G1 phase. This point is a series of safeguards to ensure the DNA is intact and that the cell is functioning normally. Functionally, the safeguards exist as proteins known as cyclin-dependent kinases (CDK). The G1 CDK proteins activate the transcription factors for a variety of genes.These include genes which are responsible for DNA synthesis proteins and S phase CDK proteins.
Read more about this topic: G1 Phase
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