title: Orientation-dependent regulation of integrated HIV-1 expression by host gene transcriptional readthrough.
abstract: Integrated HIV-1 genomes are found within actively transcribed host genes in latently infected CD4(+) T cells. Readthrough transcription of the host gene might therefore suppress HIV-1 gene expression and promote the latent infection that allows viral persistence in patients on therapy. To address the effect of host gene readthrough, we used homologous recombination to insert HIV-1 genomes in either orientation into an identical position within an intron of an actively transcribed host gene, hypoxanthine-guanine phosphoribosyltransferase (HPRT). Constructs were engineered to permit or block readthrough transcription of HPRT. Readthrough transcription inhibited HIV-1 gene expression for convergently orientated provirus but enhanced HIV-1 gene expression when HIV-1 was in the same orientation as the host gene. Orientation had a >10-fold effect on HIV-1 gene expression. Due to the nature of HIV-1 integration sites in vivo, this orientation-dependent regulation can influence the vast majority of infected cells and adds complexity to the maintenance of latency.
authors.affiliation: Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
authors.forename: Yefei
authors.initials: Y
authors.lastname: Han
authors.forename: Yijie B
authors.initials: YB
authors.lastname: Lin
authors.forename: Wenfeng
authors.initials: W
authors.lastname: An
authors.forename: Jie
authors.initials: J
authors.lastname: Xu
authors.forename: Hung-Chih
authors.initials: HC
authors.lastname: Yang
authors.forename: Karen
authors.initials: K
authors.lastname: O'Connell
authors.forename: Dominic
authors.initials: D
authors.lastname: Dordai
authors.forename: Jef D
authors.initials: JD
authors.lastname: Boeke
authors.forename: Janet D
authors.initials: JD
authors.lastname: Siliciano
authors.forename: Robert F
authors.initials: RF
authors.lastname: Siliciano
mesh_terms: D015967:Gene Expression Regulation, Viral; D045325:HCT116 Cells; D015658:HIV Infections / Q000235:genetics* / Q000821:virology; D015497:HIV-1 / Q000235:genetics* / Q000502:physiology; D006657:Histones / Q000235:genetics / Q000378:metabolism; D054884:Host-Pathogen Interactions; D006801:Humans; D007041:Hypoxanthine Phosphoribosyltransferase / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic; D014158:Transcription, Genetic; D016662:Virus Integration; D017735:Virus Latency
chemical_list: D006657:Histones; D007041:Hypoxanthine Phosphoribosyltransferase