Genetics of Retroviruses Essay Example | Topics and Well Written Essays - 1000 words

factortics of Retroviruses - Essay ExampleThe core contains two identical copies of the wiz stranded RNA genome. The RNA molecules are complexed with reverse transcriptase and tRNA. Other viral proteins like integrase are also components of the virion particle.The outer envelope glycoprotein (SU), is the major antigen of the virus, and is prudent for receptor binding. The trans-membrane glycoprotein (TM), holds the SU protein in the envelope, and is responsible for membrane fusionAll retrovirus genomes consist of two molecules of RNA, which are s/s, (+)sense and have 5 cap and 3 poly-(A) (equivalent to mRNA). These modify in size from 8-11kb. Retrovirus genomes have 4 unique featuresThese two molecules are physically linked as a dimer by hydrogen bonds (co-sediment). In addition, thither is a 3rd type of nucleic acid present in all particles, a specific type of tRNA (usually trp, pro or lys) - required for replication. Gene order in all retroviruses is invariant 5 - gag - pol - e nv - 3. The gag (group-specific antigen, core protein) gene encodes proteins that make up the nucleocapsid of the virus as tumesce as a matrix layer, the two of which surround the RNA. The pol gene (RNA-dependent DNA polymerase) encodes three proteins, reverse transcriptase, which copies the RNA into DNA, integrase, which integrates the DNA into the host chromosome and protease, a protein that cleaves the Gag-Pol polyprotein into littler protein products. The env gene encodes the envelope glycoproteins. Some retroviruses have incorporated viral oncogene sequences.( www.bookrags.com) The genomes of complex retroviruses, such as human T-cell lymphotropic virus (HTLV) contain additional genes (e.g., taxation and rex) for regulatory proteins.R Region A short (18-250nt) sequence which forms a direct repeat at the both ends of the genome, which is therefore terminally redundant.U5 A unique, non-coding share of 75-250nt