Fig. 2: mamRNA intron encodes a C/D-box snoRNA.

a dRNA-seq profile of the mamRNA and U14-encoding genomic locus. The top box shows the cumulative coverage (n = 2), with the range of reads indicated in square brackets. The bottom box shows a subset of reads (200) representative of the different read populations. The following down-sampling parameters in IGV were used: sampling window size (bases) = 230 (i.e. median read length); numbers of reads per window = 200. The blue bars correspond to intronic sequences that are absent in the corresponding reads. b Multiple sequence alignment (CLUSTALW) of S. pombe snR107, S. cerevisiae snR190 and human SNORD12/B/C. The C, D’, C’ and D boxes are highlighted in red. The antisense elements (ASE1 and ASE2) complementary to the 25S or 28S rRNAs are highlighted in magenta and orange respectively. Conserved residues are denoted with an asterisk. Nucleotides immediately upstream of the C box and downstream of the D box were excluded for the analysis. c Northern blots showing the fractions of snR107 and U14 immunoprecipitated with HTP-tagged versions of Fib1, Nop56, Nop58 and Snu13. An untagged strain was used as negative control. IP = Immunoprecipitate; WCE = Whole Cell Extract. b = bases. d, e Representative images of mamRNA and snR107 localization as detected by smFISH in cells of the indicated genetic backgrounds. DNA was stained with DAPI. Images are shown as Z-projections. Scale bar, 5 µm. Source data are provided as a Source Data file.