| Term | Definition |
|---|
| Characteristics of Viral RTs | 1. DNA polymerase requires primers 2. RNase H (endonuclease, degrades RNA in RNA: DNA hybrid molecules) 3. Error Prone (no proofreading) |
| Alpharetrovirus | Rous Sarcoma virus |
| Betaretrovirus | mouse mammary tumor virus |
| gammaretrovirus | murine leukemia virus |
| deltaretrovirus | Human t-cell leukemia virus |
| epsilonretrovirus | walleye dermal sarcoma virus |
| lentivirus | HIV |
| Spumavirus | simian foamy virus |
| Organization of Retrovirus Genome | Cap R U5 PBS GAG POL ENV PPT U3 R Poly A |
| Retrovirus pathway | RNA -> DNA -> RNA |
| Hepadnavirus pathway | DNA -> RNA -> DNA |
| RNAse H | endonuclease, degrades RNA in RNA: DNA hybrid molecules |
| 1st strand synthesis: initiation site: | PBS (tRNA binds to PBS) |
| Viral DNA must get into nucleus (2 Ways) | mitosis (when cell divides) or transport into the nucleus (HIV uses a preintegration complex) |
| Mechanism of integration | integrase recognizes LTR (sequence specific) , makes a cut in viral DNA to make sticky ends, nicks the host DNA and puts in viral DNA |
| Impact of integration on Virus | stable maintenance of viral genome, persistent infection |
| Impact of integration on host | inherently mutagenic, evolutionary consequences |
| Provirus | virus that integrates itself into the host genome |
| complex retroviruses contain: | regulatory and/or accessory genes (like tat and rev) |
| Rev | helps nucleus let out unspliced RNA |
| How does Tat activate transcription? | binds TAR, recruits cyclin T and Cdk9, phosphorylation of RNA pol II C-terminal domain, |
| What does GAG code for? | nucleocapsid proteins |
| What does Pol code for? | reverse transcriptase, protease, integrase |
| What does Env code for? | envelope proteins |
| ____ and _____ proteins are made on unspliced mRNA | GAG and POL |
| ___ proteins are made on singly spliced mRNA | ENV |
| Distinctive Characteristics of Retroviruses | two identical copies of genome/virion, genome RNA converted to DNA by reverse transcription, a cellular tRNA used as primer to initiate reverse transcription |
| Two regions are essential for TAR to function: | bulge in the stem (acts as recognition element for TAT binding) nucleotide sequence within the loop |
| TAT increaes viral abundance how? | by increasing the elongation efficiency of RNA polymerase molecules by phosphorylation |
| How does Rev work? | RNA molecule binds to it, and it allows unspliced RNA out of the nucleus through protein pores (instead of the normal spliced mRNA channel) |
| Characteristics of Acutely transforming retroviruses | simple (carry an onco-gene of cellular origin) high efficiency, short tumor latency (weeks) uncommon in nature |
| SRC | rous sarcoma virus |
| fos | murine osteosarcoma virus |
| jun | avian sarcoma virus |
| Name an acute virus | WDSV |
| Nontransducing Retroviruses Characteristics | simple retroviruses that do NOT carry oncogenes, promoter or enhancer insertion (activation of cellular oncogene), long tumor latency |
| characteristics of transactivating retroviruses | growth stimulation of neighboring cells, complex retroviruses, HTLV-1, transforming capability due to pleiotropic effects of viral transactivator |
| rex | rev homolog |
| tax | tat homolog |
Combine with other sets
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