Figure 5.

Human pre-rRNA processing and ITS1 and C-box similarity in mammals. Schematic presentation of the human RNA polymerase transcript—45Svpre-rRNA (upper panel), processing sites are marked as reviewed in Mullineux and Lafontaine⁶¹. UCE—upstream control element; CP—core promoter; IGS—an intergenic spacer; 5′ETS and 3′ETS—5′ and 3′ external transcribed spacers; ITS1 and ITS2—internal transcribed spacers 1 and 2. Conservation in mammals is indicated by shades of grey (a middle panel); C-box is shown in violet box. The C-box nucleotide sequence is shown for human chromosome 22 (this study; bottom panel); the locations of human variants (INDELs) in the C-box are highlighted in blue. C-box conservation by Phylop (brown and blue) and by PhastCons (green) from the Multiz alignment of 30 mammals is shown in the bottom panel (UCSC genome browser—https://genome.ucsc.edu/cgi-bin/hgGateway?hgsid=970436711_JhFQiQl4MIataJe6MUxuOqVnPRWz).