The ribotoxin α-sarcin can cleave the sarcin/ricin loop on late 60S pre-ribosomes.
Nucleic Acids Res
; 48(11): 6210-6222, 2020 06 19.
Article
en En
| MEDLINE
| ID: mdl-32365182
ABSTRACT
The ribotoxin α-sarcin belongs to a family of ribonucleases that cleave the sarcin/ricin loop (SRL), a critical functional rRNA element within the large ribosomal subunit (60S), thereby abolishing translation. Whether α-sarcin targets the SRL only in mature 60S subunits remains unresolved. Here, we show that, in yeast, α-sarcin can cleave SRLs within late 60S pre-ribosomes containing mature 25S rRNA but not nucleolar/nuclear 60S pre-ribosomes containing 27S pre-rRNA in vivo. Conditional expression of α-sarcin is lethal, but does not impede early pre-rRNA processing, nuclear export and the cytoplasmic maturation of 60S pre-ribosomes. Thus, SRL-cleaved containing late 60S pre-ribosomes seem to escape cytoplasmic proofreading steps. Polysome analyses revealed that SRL-cleaved 60S ribosomal subunits form 80S initiation complexes, but fail to progress to the step of translation elongation. We suggest that the functional integrity of a α-sarcin cleaved SRL might be assessed only during translation.
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Ricina
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Saccharomyces cerevisiae
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Proteínas Fúngicas
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Endorribonucleasas
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Subunidades Ribosómicas Grandes de Eucariotas
Idioma:
En
Revista:
Nucleic Acids Res
Año:
2020
Tipo del documento:
Article
País de afiliación:
España