title: The lysogenic region of virus phiCh1: identification of a repressor-operator system and determination of its activity in halophilic Archaea.
abstract: phiCh1 is a temperate virus infecting the haloalkaliphilic archaeon Natrialba magadii. As for all temperate viruses, a control of the lysogenic state versus the lytic life cycle is essential. Two open reading frames (ORFs) have been identified as putative repressor encoding genes: ORF48 and ORF49. The protein of ORF48 showed sequence similarities to putative repressor molecules. ORF49 was identified by the analysis of a mutant of phiCh1: the lysogenic strain carrying mutant phiCh1-1 showed a different lysis behavior than wild type virus phiCh1, indicating a dysfunction in the regulation of gene expression. Here, we show that the intergenic region between ORF48 and ORF49 comprises a promoter/operator sequence that is a transcriptionally active region in the model system Haloferax volcanii. Transcription from this region can be repressed by the activity of the ORF48 gene product. Gp43/gp44 has an enhancing effect on this regulatory sequence. Evidence is given for a possible binding site of Rep and gp43/gp44 within the coding region of the rep gene.
authors.affiliation: Department of Microbiology and Immunobiology, Max F. Perutz Laboratories, University of Vienna, Dr. Bohr-Gasse 9, Vienna, 1030, Austria.
authors.forename: M
authors.initials: M
authors.lastname: Iro
authors.forename: R
authors.initials: R
authors.lastname: Klein
authors.forename: B
authors.initials: B
authors.lastname: Gálos
authors.forename: U
authors.initials: U
authors.lastname: Baranyi
authors.forename: N
authors.initials: N
authors.lastname: Rössler
authors.forename: A
authors.initials: A
authors.lastname: Witte
mesh_terms: D023641:Archaeal Viruses / Q000235:genetics* / Q000378:metabolism; D015967:Gene Expression Regulation, Viral / Q000502:physiology; D016931:Halobacteriales / Q000235:genetics / Q000821:virology*; D008242:Lysogeny / Q000235:genetics*; D009154:Mutation; D016366:Open Reading Frames; D009875:Operator Regions, Genetic; D011401:Promoter Regions, Genetic; D012097:Repressor Proteins / Q000235:genetics*; D014158:Transcription, Genetic / Q000502:physiology; D014764:Viral Proteins / Q000235:genetics* / Q000378:metabolism
chemical_list: D012097:Repressor Proteins; D014764:Viral Proteins