Expression and modification by ribose methylation of early- and late-rRNA types of rRNA in zebrafish. (A) Schematic illustration of genomic localization, 2′-O-Me modification, and the prevalence of expressed early- and late-rRNA. The rRNA biogenesis symbolized by the arrow involves multiple steps and several types of modifications, but only ribose methylation, relevant for the present study, is illustrated. Here, an example of a canonical interaction between a box C/D guide RNA (SNORD) and its rRNA target is shown with indication of the methyl group introduced in red. (B) Bright field microscope images of the developmental stages analyzed in the present study: (Unf. Egg) unfertilized egg, the 32-cell stage, the 12-somite stage, and (PM) protruding-mouth stage. (C) Estimated relative expression (±SEM) of early- and late-SSU rRNA (left) and LSU rRNA (right) based on SNP analysis of reads from RiboMeth-seq. The result is based on the analysis of four diagnostic nucleotides in SSU and seven diagnostic nucleotides in LSU, respectively. n = 3. (D) Venn-diagrams depicting the conservation of ribose-methylated sites in SSU, LSU, and 5.8S between human rRNA and zebrafish early- and late-rRNA subtypes, respectively.
