Oncogenes Flashcards
oncogene
cancer-inducing gene; can transform cells
oncoprotein
protein product of an oncogene
tumor suppressor gene
a gene whose partial or complete inactivation increases likelihood of cancer development
two sources of oncogenes
viral infection and cellular
retroviral oncogenes
stolen from host; RSV
human tumor virus oncogenes
evolved as part of virus
rous sarcome virus
src gene
spontaneous point mutation of proto-oncogene
glycine to valine causes Ras to become an oncogene by inhibiting GAP activity –> will always be on
mutation of regulatory sequence (telomerase)
promoter mutation of hTERT causing increased expression –> more telomerase means cells do not die
gene amplification of proto-oncogenes
erbB2/HER2 duplications linked to cancer
homogeneously staining region
tandem arrays of myc gene
myc-myc or myc-max
activates transcription of genes encoding growth-promoting factors (cyclin D and E2F)
myc-miz/mxd
represses transcription of genes encoding cell cycle inhibitors (p15, p21, p27)
Burkitt’s lymphoma
myc on chromosome 8 translocates to IgH on chromosome 14 –> myc expression is now being driven as if it were an antibody
HMGA2
component of chromatin that facilitates DNA architectural changes at promoter regions –> negatively regulated by Let-7
HMGA-2 mutation
Let-7 cannot bind to repress, causing it to now act as an oncoprotein
philadelphia chromosome
translocation between chromosome 9 and 22 causes chronic myeloid leukemia
philadelphia chromosome effect
Bcr-Abl fusion results in a constitutively active kinase
viral causes of cancer in humans
HPV and HepB/C
E7 of HPV
inactivates pRb
E6 of HPV
inactivates p53
E5 of HPV
increases EGFR
tax oncoprotein
HTLV; activates NF-kappaB which induces pro-survival genes
