Identification of three novel noncoding RNAs from Drosophila melanogaster

Three novel small noncoding RNAs were identified from the conserved intronic regions of D. melanogaster by using comparative genomics method and molecular biology approach. One is a novel snoRNA in a combinated way, which displays structural features typical of C/D box snoRNA family and possesses a 10-nt-long rRNA antisense element for guiding the 2′-O-methylation of the D. melanogaster 28S rRNA at C2673. The other two are miRNAs whose predicted precursors adopt a stemloop structure characteristic of known miRNA. The two miRNAs genes appear to have ubiquitous expression profiles with ∼23-nt RNA transcripts detected by Northern blotting. Our study revealed 396 multi-species intronic conserved sequences (MCIS) that nested in the introns with a length from 100 to 500 bp. In addition to small RNA coding, the MCIS might function as cis-acting elements involved in gene transcription or post-transcriptional processing.