SnoRNA guide activities: real and ambiguous.
RNA
; 27(11): 1363-1373, 2021 11.
Article
em En
| MEDLINE
| ID: mdl-34385348
ABSTRACT
In eukaryotes, rRNAs and spliceosomal snRNAs are heavily modified post-transcriptionally. Pseudouridylation and 2'-O-methylation are the most abundant types of RNA modifications. They are mediated by modification guide RNAs, also known as small nucleolar (sno)RNAs and small Cajal body-specific (sca)RNAs. We used yeast and vertebrate cells to test guide activities predicted for a number of snoRNAs, based on their regions of complementarity with rRNAs. We showed that human SNORA24 is a genuine guide RNA for 18S-Ψ609, despite some noncanonical base-pairing with its target. At the same time, we found quite a few snoRNAs that have the ability to base-pair with rRNAs and can induce predicted modifications in artificial substrate RNAs, but do not modify the same target sequence within endogenous rRNA molecules. Furthermore, certain fragments of rRNAs can be modified by the endogenous yeast modification machinery when inserted into an artificial backbone RNA, even though the same sequences are not modified in endogenous yeast rRNAs. In Xenopus cells, a guide RNA generated from scaRNA, but not from snoRNA, could induce an additional pseudouridylation of U2 snRNA at position 60; both guide RNAs were equally active on a U2 snRNA-specific substrate in yeast cells. Thus, post-transcriptional modification of functionally important RNAs, such as rRNAs and snRNAs, is highly regulated and more complex than simply strong base-pairing between a guide RNA and substrate RNA. We discuss possible regulatory roles for these unexpected modifications.
Palavras-chave
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Pseudouridina
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Processamento Pós-Transcricional do RNA
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Spliceossomos
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RNA Guia de Cinetoplastídeos
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Corpos Enovelados
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RNA Nucleolar Pequeno
Limite:
Humans
Idioma:
En
Revista:
RNA
Assunto da revista:
BIOLOGIA MOLECULAR
Ano de publicação:
2021
Tipo de documento:
Article
País de afiliação:
Estados Unidos