Characterization of the intron-encoded U19 RNA, a new mammalian small nucleolar RNA that is not associated with fibrillarin.

AUTOR(ES)

Kiss, T

RESUMO

We have characterized a new member (U19) of a group of mammalian small nuclear RNAs that are not precipitable with antibodies against fibrillarin, a conserved nucleolar protein associated with most of the small nucleolar RNAs characterized to date. Human U19 RNA is 200 nucleotides long and possesses 5'-monophosphate and 3'-hydroxyl termini. It lacks functional boxes C and D, sequence motifs required for fibrillarin binding in many other snoRNAs. Human and mouse RNA are 86% homologous and can be folded into similar secondary structures, a finding supported by the results of nuclease probing of the RNA. In the human genome, U19 RNA is encoded in the intron of an as yet not fully characterized gene and could be faithfully processed from a longer precursor RNA in HeLa cell extracts. During fractionation of HeLa cell nucleolar extracts on glycerol gradients, U19 RNA was associated with higher-order structures of approximately 65S, cosedimenting with complexes containing 7-2/MRP RNA, a conserved nucleolar RNA shown to be involved in 5.8S rRNA processing in yeast cells.

Documentos Relacionados

• Fibrillarin Is Essential for Early Development and Required for Accumulation of an Intron-Encoded Small Nucleolar RNA in the Mouse
• In vitro study of processing of the intron-encoded U16 small nucleolar RNA in Xenopus laevis.
• U24, a novel intron-encoded small nucleolar RNA with two 12 nt long, phylogenetically conserved complementarities to 28S rRNA.
• Processing of the Intron-Encoded U18 Small Nucleolar RNA in the Yeast Saccharomyces cerevisiae Relies on Both Exo- and Endonucleolytic Activities
• U20, a novel small nucleolar RNA, is encoded in an intron of the nucleolin gene in mammals.