MBG 3050 Lecture Notes - Lecture 18: P21, P53, Gsk-3
2 Jan 2016
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18 supplement gatekeeper = regulator of cell cycle or cause growth inhibition caretaker = repairs dna damage and maintain genome integrity. Mendelian (inherited) retinoblastoma: dominant inheritance > vertical (every generation has the phenotype) recessive mechanism > both alleles altered acquires a somatic mutation in rapidly dividing cells (common in growing children) multiple tumours bilateral earlier onset. Sporadic retinoblastoma: must acquire two somatic mutations of the same gene single tumour unilateral later onset (time needed to acquire mutations) Loss of heterozygosity (loh): commonly associated with tsgs (ex. Rb) occurs when a somatic cell contain only one functional copy of a gene second copy is lost due to deletion or other mutational event in cancer we often see undermethylation and overexpression. Role of prb: prb represses tfs such as e2f upon cdk phosphorylation of prb, e2f is released. E2f activates its target genes the cell cycle is able to progress past the start checkpoint.
