ERV

Question 1

Gag gene

Answer 1

Codes for a poly protein which is processed by viral protease into three small proteins: matrix, capsid, nucleocapsid. Major component of the viral capsid and are responsible for recognizing, binding, and packaging the retro viral genomic RNA.

Question 2

Pro gene

Answer 2

Codes for viral protease employed in maturation of Gag and Pol poly proteins

Question 3

Pol gene

Answer 3

Codes for reverse transcriptase, integrase, and RNase H (degrades the RNA strand from the RNA-DNA heteroduplex)

Question 4

Env gene

Answer 4

Encodes the envelope protein, synthesized as precursors and cleaved into two subunits: SU and TM; very immunogenic due to constant exposure to host immune system

Question 5

Accessory protein of retrovirus?

Answer 5

1. Rev, Rex, Rec (homologous between HIV, HTLV, HERV-K): bind to highly structured motifs of viral mRNAs termed ‘responsive elements’ and export them from nucleus to cytoplasm for protein production
2. Tat for HIV and Tax for HTLV: binds to the TAR region of viral RNA and increase RNA synthesis