title: Transcription termination signals in the nin region of bacteriophage lambda: identification of Rho-dependent termination regions.
abstract: The approximately 3-kb nin region of bacteriophage lambda, located between genes P and Q contains transcription termination signals as well as 10 open reading frames. Deletions in the nin region frees phage growth from dependence on the lambda-encoded N-transcription antitermination system, conferring a Nin phenotype (N-independence). A subregion of nin, roc, is defined by a 1.9-kb deletion (delta roc) which partially frees lambda growth from the requirement for N antitermination. The roc region has strong transcription termination activity as assayed by a plasmid-based terminator testing system. We report the following features of the roc region: the biologically significant terminators in the roc region are Rho dependent, deletion analysis located the biologically significant termination signals to a 1.2 kb-segment of roc, and analysis of other deletions and point mutations in the roc region suggested at least two biologically significant regions of termination, tR3 (extending from bp 42020 to 42231) and tR4 (extending from bp 42630 to 42825).
authors.affiliation: Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor 48109-0620, USA.
authors.forename: S W
authors.initials: SW
authors.lastname: Cheng
authors.forename: D L
authors.initials: DL
authors.lastname: Court
authors.forename: D I
authors.initials: DI
authors.lastname: Friedman
mesh_terms: D010582:Bacteriophage lambda / Q000235:genetics* / Q000254:growth & development; D001483:Base Sequence; D003062:Codon; D003433:Crosses, Genetic; D004926:Escherichia coli / Q000235:genetics*; D016368:Frameshift Mutation; D015967:Gene Expression Regulation, Viral; D005814:Genes, Viral; D005838:Genotype; D008969:Molecular Sequence Data; D016296:Mutagenesis; D016366:Open Reading Frames; D010957:Plasmids; D014176:Protein Biosynthesis; D015183:Restriction Mapping; D012234:Rho Factor / Q000378:metabolism*; D017384:Sequence Deletion; D013728:Terminator Regions, Genetic; D014158:Transcription, Genetic
chemical_list: D003062:Codon; D012234:Rho Factor