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oai:docta.ucm.es:20.500.14352/65522024-09-23T17:44:35Zcom_20.500.14352_14col_20.500.14352_15

00925njm 22002777a 4500 dc Olombrada, Miriam author Peña, Cohue author Rodríguez Galán, Olga author Klingauf Nerurkar, Purnima author Portugal Calisto, Daniela author Oborská Oplová, Michaela author Altvater, Martin author Gavilanes, José G. author Martínez Del Pozo, Álvaro author De la Cruz, Jesús author García Ortega, Lucía author Govind Panse, Vikram author 2020-04-04 The 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. 1362-4962 10.1093/nar/gkaa315 https://hdl.handle.net/20.500.14352/6552 https://doi.org/10.1093/nar/gkaa315 https://academic.oup.com/nar/article/48/11/6210/5828919 The ribotoxin α-sarcin can cleave the sarcin/ricin loop on late 60S pre-ribosomes