Emergence of the primordial pre-60S from the 90S pre-ribosome.
Cell Rep
; 39(1): 110640, 2022 04 05.
Article
in En
| MEDLINE
| ID: mdl-35385737
ABSTRACT
Synthesis of ribosomes begins in the nucleolus with formation of the 90S pre-ribosome, during which the pre-40S and pre-60S pathways diverge by pre-rRNA cleavage. However, it remains unclear how, after this uncoupling, the earliest pre-60S subunit continues to develop. Here, we reveal a large-subunit intermediate at the beginning of its construction when still linked to the 90S, the precursor to the 40S subunit. This primordial pre-60S is characterized by the SPOUT domain methyltransferase Upa1-Upa2, large α-solenoid scaffolds, Mak5, one of several RNA helicases, and two small nucleolar RNA (snoRNAs), C/D box snR190 and H/ACA box snR37. The emerging pre-60S does not efficiently disconnect from the 90S pre-ribosome in a dominant mak5 helicase mutant, allowing a 70-nm 90S-pre-60S bipartite particle to be visualized by electron microscopy. Our study provides insight into the assembly pathway when the still-connected nascent 40S and 60S subunits are beginning to separate.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Ribosomes
/
Saccharomyces cerevisiae Proteins
/
Ribosome Subunits, Large, Eukaryotic
Language:
En
Journal:
Cell Rep
Year:
2022
Document type:
Article
Affiliation country:
Germany