title: The start site of the Acanthamoeba castellanii ribosomal RNA transcription unit.
abstract: The 39S ribosomal RNA (rRNA) precursor has been isolated from Acanthamoeba castellanii. In vitro capping of the isolated RNA verified that it is the primary transcript and identified the 5' nucleotide as pppA. The position of the 5' coding nucleotide on the rRNA repeat unit sequence was identified using Northern blot, R-loop, and S1 nuclease mapping techniques. Dinucleotide priming of an in vitro transcription system stalled because of low initiating nucleotide concentration revealed that ApA maximally stimulates initiation of transcription. All of these results show that the underlined A in the sequence 5'-TATATATAAAGGGAC (RNA-like strand) coincides with the 5' nucleotide of the primary transcript. This identification is compatible with in vitro transcription experiments mapping the promoter for this transcription unit. The initiation sequences of rRNA genes from 14 species are compared, and a weak consensus for the initiator derived: [Formula; see text].
authors.affiliation: Department of Biochemistry, Colorado State University, Fort Collins 80523.
authors.forename: P J
authors.initials: PJ
authors.lastname: Perna
authors.forename: G H
authors.initials: GH
authors.lastname: Harris
authors.forename: C T
authors.initials: CT
authors.lastname: Iida
authors.forename: P
authors.initials: P
authors.lastname: Kownin
authors.forename: S
authors.initials: S
authors.lastname: Bugren
authors.forename: M R
authors.initials: MR
authors.lastname: Paule
mesh_terms: D000048:Acanthamoeba / Q000235:genetics*; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D002474:Cell-Free System; D003001:Cloning, Molecular; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D012322:RNA Precursors / Q000302:isolation & purification; D016053:RNA, Protozoan / Q000235:genetics*; D012335:RNA, Ribosomal / Q000235:genetics*; D015719:Single-Strand Specific DNA and RNA Endonucleases; D014158:Transcription, Genetic
chemical_list: D012322:RNA Precursors; D016053:RNA, Protozoan; D012335:RNA, Ribosomal; D015719:Single-Strand Specific DNA and RNA Endonucleases