ONCOL320 Lecture Notes - Lecture 11: Myc, Superoxide Dismutase, Melanosome
31 Oct 2016
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Passed on to the daughter cell during cell division ex. Dna damage: chemical or physical alteration in the structure of dna ex. Pyrimidine dimers (tt, cc), double-stranded breaks, alkylation damage, oxidative damage. Mutations can be a result of imperfectly repaired damage. Spontaneous breakdown of nucleotides after incorporation into dna. Prevention is better than treatment - keep mutation rates low and protect stem cells. Removal of damaged nucleotides prior to incorporation into dna. Polymerase inserts only nucleotides that base-pair with template (a-t; g-c) In eukaryotes, each polymerase is composed of many subunits. Dna synthesis is always in the 5" to 3" direction. G in the template pairs with t instead of c) are detected immediately. Transgenic mice with a point mutation in the proofreading domain of dna polymerase (d400a) - synthesis activity still intact. Mismatch repair (mmr) enzymes monitor recently-synthesized dna and correct copy errors. Errors can occur in repeat regions (called microsatellite repeats) by polymerase stuttering
