Functional Characterization of XendoU, the Endoribonuclease Involved in Small Nucleolar RNA Biosynthesis

XendoU is the endoribonuclease involved in the biosynthesis of a specific subclass of Xenopus laevis intron-encoded small nucleolar RNAs. XendoU has no homology to any known cellular RNase, although it has sequence similarity with proteins tentatively annotated as serine proteases. It has been recen...

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Bibliographic Details
Published in:The Journal of biological chemistry 2005-05, Vol.280 (19), p.18996-19002
Main Authors: Gioia, Ubaldo, Laneve, Pietro, Dlakić, Mensur, Arceci, Massimo, Bozzoni, Irene, Caffarelli, Elisa
Format: Article
Language:English
Subjects:
Amino Acid Sequence
Animals
Catalysis
Catalytic Domain
Cloning, Molecular
DNA Primers - chemistry
Endoribonucleases - chemistry
Endoribonucleases - physiology
Glutamic Acid - chemistry
Histidine - chemistry
Introns
Lysine - chemistry
Manganese - chemistry
Molecular Sequence Data
Mutation
Oligopeptides - chemistry
Phylogeny
Plasmids - metabolism
Protein Binding
Protein Structure, Tertiary
Recombinant Proteins - chemistry
RNA, Small Nuclear - metabolism
Sequence Homology, Amino Acid
Substrate Specificity
Transcription, Genetic
Xenopus
Xenopus laevis
Xenopus Proteins - chemistry
Xenopus Proteins - physiology
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Summary:XendoU is the endoribonuclease involved in the biosynthesis of a specific subclass of Xenopus laevis intron-encoded small nucleolar RNAs. XendoU has no homology to any known cellular RNase, although it has sequence similarity with proteins tentatively annotated as serine proteases. It has been recently shown that XendoU represents the cellular counterpart of a nidovirus replicative endoribonuclease (NendoU), which plays a critical role in viral replication and transcription. In this paper, we combined prediction and experimental data to define the amino acid residues directly involved in XendoU catalysis. Specifically, we find that XendoU residues Glu-161, Glu-167, His-162, His-178, and Lys-224 are essential for RNA cleavage, which occurs in the presence of manganese ions. Furthermore, we identified the RNA sequence required for XendoU binding and showed that the formation of XendoU-RNA complex is Mn2+-independent.
ISSN:0021-9258
1083-351X
DOI:10.1074/jbc.M501160200