Olombrada, MiriamPeña, CohueRodríguez Galán, OlgaKlingauf Nerurkar, PurnimaPortugal Calisto, DanielaOborská Oplová, MichaelaAltvater, MartinGavilanes, José G.Martínez Del Pozo, ÁlvaroCruz, Jesús de laGarcía Ortega, LucíaGovind Panse, Vikram2023-06-162023-06-1620201362-4962doi.org/10.1093/nar/gkaa315https://hdl.handle.net/20.500.14352/6574The ribotoxin -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 -sarcin targets the SRL only in mature 60S subunits remains unresolved. Here, we show that, in yeast, -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 -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 -sarcin cleaved SRL might be assessed only during translation.engAtribución-NoComercial 3.0 Españahttps://creativecommons.org/licenses/by-nc/3.0/es/journal articlehttps://doi.org/10.1093/nar/gkaa315https://academic.oup.com/nar/article/48/11/6210/5828919open access577.1RibosomesPeptide Elongation Factor GAnticodonsBiología molecular (Química)Bioquímica (Química)