30章反转录病毒ppt.ppt

Sexually Transmitted Disease STD Retroviridae a large group RNA viruses containing reverse transcriptase. Oncovirinae: Lentivirinae: slowly progressive diseases, HIV and equine infectious anaemia virus, Spumavirinae: not associated with disease Common features ⑴ The viruses are spherical, have a envelope, have spikes on the surface and are about 100nm. ⑵ Viral core is composed of two molecules of single RNA, which construct central nucleoid with endo-capsid. Viruses, which nucleoid are condensed and round in shape, are known as type C viral particles while those with an eccentric bar structure or cylindrical nucleoid are type D particles. ⑶ The genome organization is similar for all retroviruses in that their genomes contain in the same order the genes gag, pol and env, which code for the three groups of structural proteins, and several regulatory genes. ⑷ In the virions, are contained reverse transcriptase, RNA-dependent DNA polymerase, RNase H, and endonuclease. ⑸ The character of viral proliferation: When viral RNA are replicated, cDNA is first synthesized with the effect of reverse trascriptase forming RNA:DNA replicative intermediate. Human immunodeficiency virus HIV—Human cancer virus HIV---pathogen of acquired immunodeficiency syndrome, AIDS HIV: HIV-1 and HIV-2 1 .properties： （1) 100～120nm，spherical, core-cylindrical and composed of two same single positive RNA, 2. Genome and function （1）structure genes： ① env gene: codes glycoprotein (gp); gp41, the transmembrane component and mediate the fusion of viral envelope and cell membrane of host， gp120, the external envelope glycoprotein，on which amino sequence there are bonding sites with antibody and CD4 molecules. ②? pol gene: a protease(p11), endonuclease, integrase(p32) ， reverse transcriptase(p66/p51)with the function of polymerase and RNase H—no proof-reading. ③? gag gene: codes for four proteins, all found within the virion. P55-----P24,P17 and P15，the later—P7and P-6