mutagenesis review deck Flashcards
5 types of endogenous mutations
oxidation of bases alkylation of bases hydrolysis of bases (includes deamination) bulky adduct formation mismatch of bases
what is the result of C deamination?
C to U yields C –> T point mutation
what is the result of A deamination?
A to HX yields A –> G point mutation
what is the result of methyl C deamination?
methyl C to T, no repair possible
what can trigger deamination? what can inhibit is?
nitrates in foods can trigger, vitamin C can inhibit
5 types of exogenous mutations
ultraviolet radiation ionizing radiation elevated temperature lifestyle choices intercalators
what are the consequences of UVB vs. UVA exposure?
UVB- forms pyridimine dimers, direct DNA damage
UVA- forms free radicals, indirect DNA damage
by what mechanism does ionizing radiation cause mutations?
DNA strand breaks occur through the formation of OH- that reacts with C4’ and creates unstable intermediates
what is the effect of elevated temperature on DNA?
increased rate of deprivation, single-stranded breaks in DNA
how does smoking result in mutations?
creates benzopyrene, which is an intercalator
what are intercalators?
substances that mimic normal purine and pyridimines, insert into DNA and disrupt replication and transcription
what are the 3 intercalators discussed?
benzyprene (smoking), aflatoxin (mold), nitrogen mustard
what is the effect of aflatoxin?
when activated, it conjugates to a base, forms a bulky adduct
what is the effect of nitrogen mustard?
inter and intrastrand ligation
in chemo, what do the “alkylating agents” do?
cross-link DNA and form adducts
