LIFESCI 2G03 Test 1

LIFESCI 2G03 Test 1
mutation
a change in the DNA sequence
germline mutation
heritable, occurs in germ-line cells, and is passed on/present in all cells of the progeny
somatic mutation
non heritable, does not occur in germ-line cells, is not passed onto progeny, is passed
onto all descendants of that cell
what regions of the DNA are affected by germline and somatic mutations, respectively?
both types of mutations may affect the protein coding regions or the non-coding regions
what is the effect of mutations in protein coding regions?
affects the polypeptide sequence, and may impact protein function
what is the effect of mutations in non-coding regions?
in non-coding RNA: impacts gene expression
in introns: impacts polypeptide sequence
wildtype allele
the more abundant allele
mutant allele
the more rare allele
loss of function mutation + the 2 types
reduces or abolishes protein function.
1. null (amorphic): complete loss of protein function
2. hypomorphic: incomplete, reduced activity
gain of function mutation + the 3 types
increased activity or new function; or expression in the wrong place/time
1. hypermorphic: more protein or increased activity
2. neomorphic: generates a new function
3.dominant negative/anti-morphic: prevents the normal protein from performing its
homeostatic function
are loss-of-function and gain-of-function mutations usually dominant or recessive?
-loss of function: can be either
-gain of function: almost always dominant
Tp53
transcription factor that acts as the gatekeeper of cell cycle progression; stopping the
cell cycle if there is DNA damage; tumor suppressor
what is Tp53 supposed to do when there is damaged DNA?
promote apoptosis genes, promote DNA repair genes, and inhibit cell cycle genes
DBD + function
the DNA binding domain, important for Tp53 to bind to DNA and regulate transcription
What happens when there is a loss of function of DBD?