Fine structure of ribosomal RNA: III. Location of evolutionarily conserved regions within ribosomal DNA

摘要: Abstract In order to define functional regions within ribosomal RNA, we have identified areas of the molecule which been conserved during evolution. Our previous studies showed that there is evolutionary conservation between rRNAs different eukaryotes and sequences distantly related species are a subset those closely species. present work, employed DNA-DNA DNA-RNA hybridization techniques localize these mapped restriction fragments 50 300 base-pairs in length cloned Xenopus laevis DNA. experiments detected only coding regions, suggesting if any spacers, must be very short. Regions can classified either by distance or extent two Three including one near 3' end 18 S 28 rRNA over great distance, Escherichia coli X. laevis. addition, several central portions 188 exceptional their yeast Xenopus. We able correlate defined as with certain structural roles, such initiation translation, possible interaction transfer methylation, site where intervening interrupt some eukaryotic rRNAs. As result, serve relatively short (less than base-pairs) segments almost 11,000 base rDNA repeat unit worthy further investigation.