title: Cloning of Rous sarcoma virus enhancer factor genes. II. RSV-EF-II, abundantly expressed in fibroblasts and muscle tissue, binds to an octamer sequence, 5'-GTACCACC-3', in the noncoding strand of RSV enhancer.
abstract: Rous sarcoma virus (RSV) mainly replicates in avian fibroblasts, and the U3 enhancer region of the long terminal repeats of RSV contains the determinants for its tissue-tropic expression. We describe the cloning and characterization of an avian gene that encodes a protein capable of binding to the enhancer region of Rous sarcoma virus. A PCR-derived probe corresponding to the U3 region of RSV was used to isolate a cDNA clone by screening a chicken cDNA expression library. The cDNA is predicted to encode a polypeptide of 298 amino acids that is homologous to the Y-box (inverted CCAAT) family of DNA-binding transcription factors. This factor, which we refer to as Rous sarcoma virus enhancer factor-II (RSV-EF-II), shows 99% aa identity over a 105-amino-acid stretch that is highly conserved in all Y-box proteins, and is commonly referred to as the cold shock domain. RSV-EF-II selectively binds to single-stranded DNA, and the binding site, as determined by electrophoretic mobility shift assays, consists of the sequence 5' GTACCACC 3' located between nucleotides -112 to -119 in the noncoding strand of the RSV enhancer. Although RSV-EF-II shares considerable homology with the Y-box family of proteins, it does not bind to the inverted CCAAT boxes at positions -65 to -69 and -129 to -133 in the RSV LTR. Northern analysis indicates that RSV-EF-II-specific transcripts are expressed predominantly in avian fibroblasts and muscle tissue. The results of these binding and mRNA expression expriments suggest that RSV-EF-II may play an important role in tissue- and host-specific expression of RSV LTR-driven gene expression. Further, we show that RSV-EF-II acts as a repressor of transcription.
authors.affiliation: Department of Molecular Microbiology and Immunology, University of Missouri School of Medicine, Columbia 65212, USA.
authors.forename: P J
authors.initials: PJ
authors.lastname: Cleavinger
authors.forename: B A
authors.initials: BA
authors.lastname: Shin
authors.forename: J C
authors.initials: JC
authors.lastname: Kandala
authors.forename: A
authors.initials: A
authors.lastname: Nambiar
authors.forename: S K
authors.initials: SK
authors.lastname: Swamynathan
authors.forename: R V
authors.initials: RV
authors.lastname: Guntaka
mesh_terms: D016475:3T3 Cells; D000595:Amino Acid Sequence; D000818:Animals; D030161:Avian Proteins; D001358:Avian Sarcoma Viruses / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D002460:Cell Line; D002642:Chick Embryo; D003001:Cloning, Molecular; D006224:Cricetinae; D004279:DNA, Viral / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism*; D004742:Enhancer Elements, Genetic; D005347:Fibroblasts / Q000378:metabolism; D015967:Gene Expression Regulation, Viral; D051379:Mice; D008969:Molecular Sequence Data; D009132:Muscles / Q000378:metabolism; D051381:Rats; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism
chemical_list: D030161:Avian Proteins; D004279:DNA, Viral; D004268:DNA-Binding Proteins; D014157:Transcription Factors; C101555:YB-2 protein, Gallus gallus