BIOL239 Lecture Notes - Lecture 12: Tumor Suppressor Gene, P53, S Phase
7 Dec 2018
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Document Summary
A genetic disorder involving mutations of cells. Not inherited but certain inherited mutations can predispose an individual to cancer. Cancer (oncogenesis) begins with the loss of cell cycle control, forming a tumour. Tumour cells undergo further changes that allow them to invade and disrupt other tissues. Other genes (and mutations) are also involved; Lack of dna repair systems (accumulation of mutations) Genes that reinstate telomerase activity (immortalize cells) Growth factor gene mutations (stimulation of cell growth when not appropriate) Cancer arises when controls over cell division no longer function properly. Tumor suppressor genes (gatekeepers of cell cycle control) include p53 (or tp53) and rb. Normally, cyclin-dependent kinase (cdk) regulated by cyclin d, binds to the start checkpoint and commits the cell to proceed to s phase. In mammals, p53 regulates g1 to s checkpoint. P53 is a protein transcription factor that induces expression of p21.
