title: Bovine leukemia virus long terminal repeat: a cell type-specific promoter.
abstract: The functional activity of the promoter unit contained within the long terminal repeat (LTR) of bovine leukemia virus (BLV) was examined by monitoring transient expression of a heterologous gene placed under its control. Various cell lines were transfected with recombinant plasmids carrying the bacterial chloramphenicol acetyltransferase (CAT) gene coupled to the BLV LTR (pBL-cat). Transient expression of CAT activity directed by the BLV LTR was observed only in the established BLV-producer cell lines derived from fetal lamb kidney (FLK) cells and bat lung cells. The amount of CAT activity transiently expressed in FLK-BLV cells was decreased approximately tenfold by deletion of LTR sequences located within a region 100 to 170 nucleotides upstream of the RNA start site. Surprisingly, removal of the region 50 base pairs downstream of the RNA initiation site to the 3'-end of the LTR reduced the expression of CAT activity by 87 percent. The BLV LTR thus appears to be an unusual promoter unit, functioning in a cell type-specific manner and possessing sequences on both the 5' and 3' sides of the RNA start site that influence gene expression.
authors.forename: D
authors.initials: D
authors.lastname: Derse
authors.forename: S J
authors.initials: SJ
authors.lastname: Caradonna
authors.forename: J W
authors.initials: JW
authors.lastname: Casey
mesh_terms: D000818:Animals; D002417:Cattle; D002460:Cell Line; D002685:Chiroptera; D004274:DNA, Recombinant / Q000378:metabolism; D017977:Deltaretrovirus / Q000235:genetics; D005809:Genes, Regulator; D000882:Haplorhini; D006801:Humans; D001909:Leukemia Virus, Bovine / Q000235:genetics*; D011401:Promoter Regions, Genetic; D012367:RNA, Viral / Q000235:genetics*; D012091:Repetitive Sequences, Nucleic Acid; D012190:Retroviridae / Q000235:genetics*; D012756:Sheep; D014158:Transcription, Genetic
chemical_list: D004274:DNA, Recombinant; D012367:RNA, Viral