BIOC 300B Chapter Notes - Chapter p. 845-854: P53, Mitosis, Holliday Junction
16 Jan 2018
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Doe snot depend on other dna molecules in the cell. Free ds dna bound by heterodimer of twoproteins: ku70 and ku80 which stabilize the ends and mark them for more changes. Act as handles used by other proteins to draw the two ds ends close together so enzymes can seal the break. Note: can take advantage of double-stranded dna repair to make target changes in eukaryotic genome. Skin disease, leads to malignant skin cancers and metastasis. Mutations occur in genes that are homologs for nucleotide-excision-repair pathway like uvrabc. Defects in other repair systems increase frequency of other tumors: Mutation in hmsh2 and hmlh1 > encode for muts and mut l of e coli (human counterparts) Some are broad and not specific to certain types of cancer: ex: p53 found mutated in more than half of cancers. Plays role in sensing dna damage (ds breaks) then either promotes dna-repair or apoptosis.
