Open AccessAcanthamoeba castellaniicontains a ribosomal RNA enhancer binding protein which stimulates TIF-IB binding and transcription under stringent conditions
Author(s) -
Qin Yang,
Catherine A. Radebaugh,
William Kubaska,
Gary Geiss,
Marvin R. Paule
Publication year - 1995
Publication title -
nucleic acids research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 9.008
H-Index - 537
eISSN - 1362-4954
pISSN - 0305-1048
DOI - 10.1093/nar/23.21.4345
Subject(s) - biology , enhancer , transcription (linguistics) , microbiology and biotechnology , spacer dna , transcription factor , promoter , ribosomal rna , rna polymerase i , rna polymerase , rna , gene , genetics , gene expression , internal transcribed spacer , linguistics , philosophy
The intergenic spacer (IGS) of Acanthamoeba castellanii rRNA genes contains repeated elements which are weak enhancers for transcription by RNA polymerase I. A protein, EBF, was identified and partially purified which binds to the enhancers and to several other sequences within the IGS, but not to other DNA fragments, including the rRNA core promoter. No consensus binding sequence could be discerned in these fragments and bound factor is in rapid equilibrium with unbound. EBF has functional characteristics similar to vertebrate upstream binding factors (UBF). Not only does it bind to the enhancer and other IGS elements, but it also stimulates binding of TIF-IB, the fundamental transcription initiation factor, to the core promoter and stimulates transcription from the promoter. Attempts to identify polypeptides with epitopes similar to rat or Xenopus laevis UBF suggest that structurally the protein from A.castellanii is not closely related to vertebrate UBF.