Details

Autor(en) / Beteiligte

• Olombrada, Miriam
• Peña, Cohue
• Rodríguez-Galán, Olga
• Klingauf-Nerurkar, Purnima
• Portugal-Calisto, Daniela
• Oborská-Oplová, Michaela
• Altvater, Martin
• Gavilanes, José G
• Martínez-del-Pozo, Álvaro
• de la Cruz, Jesús
• García-Ortega, Lucía
• Panse, Vikram Govind

Titel

The ribotoxin α-sarcin can cleave the sarcin/ricin loop on late 60S pre-ribosomes

Ist Teil von

• Nucleic acids research, 2020-06, Vol.48 (11), p.6210-6222

Erscheinungsjahr

2020

Beschreibungen/Notizen

• 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.