title: Newly discovered antiterminator RNAs in bacteriophage.
abstract: Antiterminator RNA directly modifies the transcription elongation complex so that it terminates less efficiently at intrinsic and factor-dependent terminators. These unusual RNAs were first discovered in bacteriophage HK022, where the nascent transcripts of the phage put sites promote full expression of phage genes during lytic infection. The activity of antiterminator RNA depends on specific structural elements that form as the transcript exits RNA polymerase. To further our understanding of the critical sequence features that permit RNA to serve as a transcriptional antiterminator, we have identified eight antiterminator RNA sequences in bacteriophages or prophages. There is strong sequence conservation among most of the put sequences, but sequence divergence is tolerated if critical structural elements are preserved. The most diverged antiterminator RNA is found in bacteriophage HK639. The HK639 putL transcript is an efficient antiterminator, and it has a novel structural feature that is critical for its activity. HK639 also displays a unique pattern of sensitivity to amino acid substitutions in the β' subunit zinc binding domain of RNA polymerase, adding to existing evidence that this domain interacts specifically with antiterminator RNA.
authors.affiliation: Biology Department, Western Kentucky University, Bowling Green, Kentucky 42101-1080, USA. rodney.king@wku.edu
authors.forename: Rodney A
authors.initials: RA
authors.lastname: King
authors.forename: Alice
authors.initials: A
authors.lastname: Wright
authors.forename: Courtney
authors.initials: C
authors.lastname: Miles
authors.forename: Christopher S
authors.initials: CS
authors.lastname: Pendleton
authors.forename: Andrew
authors.initials: A
authors.lastname: Ebelhar
authors.forename: Stephanie
authors.initials: S
authors.lastname: Lane
authors.forename: Prasanna Tamarapu
authors.initials: PT
authors.lastname: Parthasarathy
mesh_terms: D001435:Bacteriophages / Q000737:chemistry / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D018388:Codon, Terminator; D012321:DNA-Directed RNA Polymerases / Q000235:genetics; D004926:Escherichia coli / Q000821:virology; D015967:Gene Expression Regulation, Viral; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D012367:RNA, Viral / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D013728:Terminator Regions, Genetic; D014158:Transcription, Genetic; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D018388:Codon, Terminator; D012367:RNA, Viral; D014764:Viral Proteins; D012321:DNA-Directed RNA Polymerases