Retroviruses - Ornelles

Question 1

• Retro-elements include ___, processes ___ (RT of cell mRNA), ___s, and ___s

Answer 1

• Retro-elements include retrotransposons, processes pseudogenes (RT of cell mRNA), LINEs, and SINEs

Question 2

• ______ are numerous (30-50), unique (tRNA priming sites), ancient, and non-replicating, with fxs such as syncytial placental layer formation, MHC I and II gene duplication, and superAg protein expression

Answer 2

• Human endogenous retroviruses (HERVs) are numerous (30-50), unique (tRNA priming sites), ancient, and non-replicating, with fxs such as syncytial placental layer formation, MHC I and II gene duplication, and superAg protein expression

Question 3

• The human genome is mostly retro-elements (__%) and __% was retrovirus

Answer 3

• The human genome is mostly retro-elements (40%) and 8% was retrovirus

Question 4

• Acutely transforming retroviruses replace ___ with an ___ and confer a growth advantage (non-human)

Answer 4

• Acutely transforming retroviruses replace Env with an oncogene and confer a growth advantage (non-human)

Question 5

• Insertion into the host genome upstream from a cellular proto-oncogene can lead to potential ____ activation via the loss of the right/end ___ (transcription continues past it to the oncogene), the loss of the left/start LTR (transcription move to use the right/end LTR as start site so it will continue to the oncogene), or LTR enhancer effect on the oncogene

Answer 5

• Insertion into the host genome upstream from a cellular proto-oncogene can lead to potential oncogene activation via the loss of the right/end LTR (transcription continues past it to the oncogene), the loss of the left/start LTR (transcription move to use the right/end LTR as start site so it will continue to the oncogene), or LTR enhancer effect on the oncogene

Question 6

• Only type of virus that require integration into host genome to replicate (only ___ and ___ can integrate into human)

Answer 6

• Only type of virus that require integration into host genome to replicate (only HIV and HTLV can integrate into human)

Question 7

• Subgenomic length RNA (spliced section) encodes ___ gene: envelope, surface (SU), and transmembrane (TM) proteins, + dictates species and cell-type specificity (ecotropic—rat/mice vs. amphotropic—humans/others)

Answer 7

• Subgenomic length RNA (spliced section) encodes Env gene: envelope, surface (SU), and transmembrane (TM) proteins, + dictates species and cell-type specificity (ecotropic—rat/mice vs. amphotropic—humans/others)

Question 8

• Full length gene mRNA can be transcribed from start to 1st stop codon (____—then cleaved into MA, CA, NC), or by skipping 1st stop codon (hairpin loop lets pol slip back/change reading frame) and continuing (Pol—then cleaved into RT, IN, PR)

Answer 8

• Full length gene mRNA can be transcribed from start to 1st stop codon (Gag—then cleaved into MA, CA, NC), or by skipping 1st stop codon (hairpin loop lets pol slip back/change reading frame) and continuing (Pol—then cleaved into RT, IN, PR)

Question 9

• Retrovirus ___ cleave viral proteins in the viral particle to generate an infectious virus

Answer 9

• Retrovirus proteases cleave viral proteins in the viral particle to generate an infectious virus

Question 10

• RT includes ______, RNA–>DNA pol, DNA pol, and RNAse H (cleaves and degrades RNA portion of hybrid strand)

Answer 10

• RT includes helicase, RNADNA pol, DNA pol, and RNAse H (cleaves and degrades RNA portion of hybrid strand)

Question 11

• Life cycle: attachment–>fusion into ___ w/ loss of envelope–> partial____–> RNA–> ds cDNA via___ in ____ using _____ primer 5’ to 3’–> cDNA and integrase entry into nucleus–> loss of 2 viral bp + duplicating 4-6 pb (forms LTRs) in new host-virus genome (provirus)–>transcription–> translation assembly–> release & maturation

Answer 11

• Life cycle: attachmentfusion into PM w/ loss of envelope partial disassembly RNA ds cDNA via RT in cystoplasm using tRNA primer 5’ to 3’ cDNA and integrase entry into nucleus loss of 2 viral bp + duplicating 4-6 pb (forms LTRs) in new host-virus genome (provirus)transcription translation assembly release & maturation

Question 12

• RT viruses have an ___ and ___ core containing _____ +ssRNA hybridized at the ___’cap ends, structural proteins, viral enzymes and ____ tRNA molecules (that are copies of ____tRNA)

Answer 12

• RT viruses have an envelope and protein core containing diploid +ssRNA hybridized at the 5’cap ends, structural proteins, viral enzymes and 2 tRNA molecules (that are copies of cellular tRNA)