Characterization of a novel trypanosomatid small nucleolar RNA.

摘要

Analysis of a novel small nucleolar RNA (snoRNA-2) from Leptomonas collosoma revealed that it was encoded by a multi-copy gene, consisted of 85 nucleotides, lacked a 5' cap and possessed the C and D boxes characteristic to all snoRNAs that bind fibrillarin. Computer analysis indicated a potential for base-pairing between snoRNA-2 and 5.8S ribosomal RNA (rRNA), and 18S rRNA. The putative interaction domains obeyed the rules suggested for the interaction of guide snoRNA with its rRNA target. However,mapping the methylated sites on the 5.8S rRNA and 18S rRNA indicated that the expected site on the 5.8S was methylated, whereas the site on the 18S was not. The proposed interaction with 5.8S rRNA was further supported by the presence of psoralen cross-link sites on snoRNA-2. A GenBank search indicated that snoRNA-2 is not related to any published snoRNAs. It is suggested that methylating snoRNAs may have evolved from self-transcribed genes. Nucleotide sequence data have been submitted to GenBank underaccession number AF050095.