Differential core histone binding behavior: RNA polymerase I promoter region vs 5S rDNA positioning DNA sequences.
In order to further characterize the previously observed disruptive effect of the RNA polymerase I promoter sequence (Pol I) from Acanthamoeba castellanii on tandemly repeated 5S rDNA positioning sequences from sea urchin (Lytechinus variegatus), we compared the histone-binding ability of the isolated 199-bp Pol I promoter region to that of the 208-bp 5S rDNA and that of nucleosome core particle sequences isolated from chicken erythocytes. We found the 5S rDNA positioning sequence to be more efficient at forming nucleosomes than the RNA polymerase I promoter sequence. Nevertheless, examination of the free-DNA half-depletion points during the titrations suggested that twice as much histone had bound to the RNA polymerase I promoter sequence as to the 5S nucleosome-positioning or core particle sequences. DNA bending analysis suggested two potential DNA bending loci in the RNA polymerase I promoter, whereas only one such locus was predicted for the 5S positioning sequence. Such mixed bending signals on the RNA polymerase I promoter could favor non-nucleosomal deposition of histones on these sequences.
Georgel
Philippe T
PT
Department of Biochemistry, University of Texas Health Science Center at San Antonio, 78229-3900, USA. georgel@uthscsa.edu
Robert
Charles H
CH
D000048:Acanthamoeba; D000818:Animals; D001483:Base Sequence; D004275:DNA, Ribosomal / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D006657:Histones / Q000378:metabolism*; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009707:Nucleosomes / Q000187:drug effects / Q000378:metabolism*; D011099:Polyglutamic Acid / Q000494:pharmacology; D011401:Promoter Regions, Genetic; D012318:RNA Polymerase I / Q000096:biosynthesis*; D012341:RNA, Ribosomal, 5S / Q000096:biosynthesis; D012617:Sea Urchins
D004275:DNA, Ribosomal; D006657:Histones; D009707:Nucleosomes; D012341:RNA, Ribosomal, 5S; D011099:Polyglutamic Acid; D012318:RNA Polymerase I