SnR4 and snR45 are distinctly involved in acetylation of 18S rRNA.

<p>A) Predicted base-pairing of snR45 and U13 to helix 45 of yeast and human 18S rRNA, respectively. B) Overlaid RP-HPLC chromatograms of nucleosides derived from 18S rRNA of WT (black) and a strain carrying a <i>SNR45</i> deletion (Δsnr45, red). C) Overlaid chromatograms of the nucleosides derived from fragments isolated using mung bean nuclease assay, containing ac⁴C1280 (oligo 34) and ac⁴C1773 (oligo 45) isolated from WT (black, green) and Δsnr45 (red, blue). D) Like snR45, snR4 can base-pair to 18S rRNA via extended complementarity to helix 34 proximal to residue ac⁴C1280. E) Overlaid chromatograms of the nucleosides derived from 18S rRNA of WT (black), Δsnr4 (cyan), Δsnr45 (red) and the double mutant Δsnr4Δsnr45 (blue).