title: Characterization of the late-gene regulatory region of phage 21.
abstract: A segment of Escherichia coli bacteriophage 21 DNA encoding the late-gene regulator, Q21, and the late-gene leader RNA segment was sequenced; its structure is similar to those of the related phages lambda and 82. The leader RNA is about 45 nucleotides long and consists essentially entirely of sequences encoding the p-independent terminator that is the putative target of the antitermination activity of Q21. Like the corresponding regions of lambda and 82, the 21 late-gene promoter segment encodes an early transcription pause in vitro, at about nucleotide 18, during which Q21 presumably acts to modify RNA polymerase. The 21 Q gene, cloned in isolation, is active on the late-gene leader segment in trans, and its purified product is active as an antiterminator in vitro; Q21 represents a third late-gene antiterminator, in addition to those of lambda and 82. There is little evident similarity in the primary sequences of the three Q genes.
authors.affiliation: Section of Biochemistry, Molecular and Cell Biology, Cornell University, Ithaca, New York 14853.
authors.forename: H C
authors.initials: HC
authors.lastname: Guo
authors.forename: M
authors.initials: M
authors.lastname: Kainz
authors.forename: J W
authors.initials: JW
authors.lastname: Roberts
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D015152:Blotting, Northern; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D003090:Coliphages / Q000235:genetics*; D005686:Galactokinase / Q000096:biosynthesis; D005809:Genes, Regulator / Q000235:genetics*; D008969:Molecular Sequence Data; D012313:RNA / Q000032:analysis; D014158:Transcription, Genetic
chemical_list: D012313:RNA; D005686:Galactokinase