Retroviral Particles, Proteins and Genomes
Norbert Bannert, Uwe Fiebig and Oliver Hohn
from: Retroviruses: Molecular Biology, Genomics and Pathogenesis (Edited by: Reinhard Kurth and Norbert Bannert). Caister Academic Press, U.K. (2010)
Retroviruses, a large group of enveloped viruses named for their typical reverse transcription and integration, comprise seven genera, all of which have the basic proviral genomic structure 5' LTR-gag-pro-pol-env-3' LTR. Despite these similarities however, retroviruses have major differences with regard to their genomic organisation, protein composition, and architecture. Genera for which differences are limited to the four invariant genes - gag (group specific antigen), pro (protease), pol (polymerase) and env (envelope) - are classified as simple retroviruses, whereas genera that encode accessory proteins are classified as complex retroviruses. Despite the retroviruses' matching sequences, the flanking long terminal repeats (LTRs) are dissimilar with regard to most of their functions. This chapter describes the general and the genera-specific facets of retroviral morphology and genomic organisation, and their consequences for transcription and protein expression read more ...