Family of Retroviridae:

Family of Retroviridae:

· Lentiviruses (non-tumour-forming)

Properties of Retroviridae:

· Spherical enveloped virion, 80-100-nm

· Ribonucleoprotein in central nucleoid( concentric or truncated cone in lentiviruses) within icosahedral capsid

· Enveloped with glycoprotein peplomers

· 2 copies of linear plus sense ssRNA, each 7-10kb

· 3’ polyadenlylated tail and 5’ cap

· Reverse transcriptase as genome doesn’t serve as mRNA.

· Formation of long terminal repeats before provirus DNA inserted into host genome.

Gag, pol, env genes some regulatory genes, some oncogenes

Virology: The Non-Living Biology