title: Bacteriophage T4 Alc protein: a transcription termination factor sensing local modification of DNA.
abstract: Bacteriophage T4 Alc protein participates in shutting off host transcription after infection of E. coli. It is demonstrated that Alc acts as a site-specific termination factor. The Alc sites occur frequently in E. coli DNA, resulting in early cessation of elongation in several tested transcription units. Alc-dependent termination requires unimpeded propagation of the elongating complex as it approaches the Alc site. Temporary halting of RNA polymerase within 10-15 bp before the Alc site prevents termination. Bacteriophage T4 transcription is protected from the action of Alc by overall substitution of cytosine with 5-hydroxymethyl cytosine in T4 DNA. In vitro methylation of CpG sequences in the vicinity of an Alc site abolishes the effect of Alc. Thus, Alc-dependent termination involves local sensing of the state of cytosine modification and a short-term "memory" of recent pausing.
authors.affiliation: Public Health Research Institute, New York, New York 10016.
authors.forename: M
authors.initials: M
authors.lastname: Kashlev
authors.forename: E
authors.initials: E
authors.lastname: Nudler
authors.forename: A
authors.initials: A
authors.lastname: Goldfarb
authors.forename: T
authors.initials: T
authors.lastname: White
authors.forename: E
authors.initials: E
authors.lastname: Kutter
mesh_terms: D017122:Bacteriophage T4 / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D004279:DNA, Viral / Q000378:metabolism*; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism*; D015226:Dinucleoside Phosphates / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D008745:Methylation; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides; D013379:Substrate Specificity; D013698:Templates, Genetic; D013728:Terminator Regions, Genetic; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic; D014764:Viral Proteins / Q000378:metabolism*
chemical_list: D004279:DNA, Viral; D012321:DNA-Directed RNA Polymerases; D015226:Dinucleoside Phosphates; D009838:Oligodeoxyribonucleotides; D014157:Transcription Factors; D014764:Viral Proteins; C083729:Alc protein, Enterobacteria phage T4; C015772:CpG dinucleotide