SnoRNA U21 is also intron-encoded in Drosophila melanogaster but in a different host-gene as compared to warm-blooded vertebrates.
U21 is an intron-encoded snoRNA in vertebrates which contains a 13-nt tract of complementarity to an invariant sequence in eukaryotic 28S rRNA. Here, we report the characterization of its Drosophila melanogaster homolog which is the first case of an intron-encoded snoRNA in an invertebrate metazoan. In D. melanogaster, U21 is encoded within the ARF-1 (ADP ribosylation factor 1) gene, whereas in chicken and mammals it is found in the ribosomal protein L5 gene. In D. melanogaster, like in vertebrates, U21 is devoid of a 5' trimethylguanosine cap, thus, likely resulting from processing of intronic RNA. The only portion of U21 sequence preserved between D. melanogaster and vertebrates, in addition to the hallmark box C and box D motifs, corresponds precisely to the 13-nt complementary to rRNA, pointing to an important role of the pairing of U21 to pre-rRNA.
Renalier
M H
MH
Laboratoire de Biologie Moléculaire Eucaryote du CNRS, Université Paul-Sabatier, Toulouse, France.
Nicoloso
M
M
Qu
L H
LH
Bachellerie
J P
JP
D000818:Animals; D001483:Base Sequence; D002645:Chickens / Q000235:genetics; D018076:DNA, Complementary; D004331:Drosophila melanogaster / Q000235:genetics; D006801:Humans; D007438:Introns; D008969:Molecular Sequence Data; D012323:RNA Processing, Post-Transcriptional; D012333:RNA, Messenger; D012339:RNA, Ribosomal, 28S / Q000737:chemistry / Q000235:genetics*; D012342:RNA, Small Nuclear / Q000737:chemistry / Q000235:genetics*; D012689:Sequence Homology, Nucleic Acid
D018076:DNA, Complementary; D012333:RNA, Messenger; D012339:RNA, Ribosomal, 28S; D012342:RNA, Small Nuclear