what change in morphology happens during transformation
flat cells change to round cells
what change in behavior happens during transformation
contact inhibition- cells touch and stop growing
what change in growth patterns happen during transformation
cells are pushed through checkpoints in cell cycle so they keep growing regardless of mutations
Who discovered oncogenes
what are the 2 types of oncogenes?
v-onc and c-onc
what is another name for c-oncogenes?
cellular genes that promote cell cycle regulation
c-onc genes picked up by viruses
oncogenes alter what?
typical cell cycle regulation
what happens in the 5 stages of the cell cycle?
G1: growth phase, RNA and Protein synthesis G0: resting stage S: DNA replication G2: RNA and Protein synthesis M: Mitosis
how is the cell cycle controlled?
through checkpoints that regulate the progression of cell from one stage to another
what are the 5 normal functions of oncogenes?
growth factors growth factor receptors signal proteins cell cycle and cell death regulators transcription factors
what are 2 tumor suppressors?
p53 and RB
what are 2 growth activators:
hormones and protoncogenes
when does virus-induced transformation occur?
tumor suppressors are inactivated enhancement of growth factors
how are growth activators enhanced?
viral oncogenes are incorporated into the host genome. viral DNA is incorporated near a proto-oncogene
what are 3 transforming viruses?
papillomavirus Human herpes Hep B
what are the 4 types of retroviruses?
HTLV-1 HTLV-2 HIV1 HIV2
what does HTLV stand for?
human T-cell lymphotrophic virus
what are HTLV 1 and 2 and HIV 1 and 2 subdivided into?
oncoviruses and lentiviruses
what is a lentivirus?
slow growing virus
is HIV 1 or 2 more common?
what is the structure and class of retroviruses?
enveloped +ssRNA virus. Class VI
what is essential in recognition of target cells?
describe the order of the retroviral gene structure?
what is LTR
long terminal repeats
what is GAG made of?
nucleoid capsid, core,
what is POL made of?
RT, RNase H, Integrase
what do ENV do?
envelope proteins code for spikes
what are the 9 steps of HIV replication?
1. adsorption 2. penetration and uptake via gp41 3. Reverse transcription in cytoplasm 4. DNA replication 5. Move into nucleus for integration into host chromosomes as provirus 6. Host transcription factors bind LTR. Cytokine secretion by immune cells can enhance HIV transcription 7. Assembly 8. Budding of immature viral particle 9. Long proteins are cleaved by viral proteases now making the virus infectious
Why does HIV mutate so quickly?
lack of proofreading activity in RT
what is HAART?
highly active anti-retroviral therapy
what is the first stage of HIV?
4-8 weeks initial infection
what is the second stage of HIV?
2-10 years asymptomatic phase
what is the third stage of HIV?
2-3 years AIDS/ARC
immunosuppresion caused by HIV due to drop in TH cells to levels of <200