In:
Science, American Association for the Advancement of Science (AAAS), Vol. 369, No. 6510 ( 2020-09-18), p. 1470-1476
Abstract:
Production of small ribosomal subunits initially requires the formation of a 90 S precursor followed by an enigmatic process of restructuring into the primordial pre-40 S subunit. We elucidate this process by biochemical and cryo–electron microscopy analysis of intermediates along this pathway in yeast. First, the remodeling RNA helicase Dhr1 engages the 90 S pre-ribosome, followed by Utp24 endonuclease–driven RNA cleavage at site A 1 , thereby separating the 5′-external transcribed spacer (ETS) from 18 S ribosomal RNA. Next, the 5′-ETS and 90 S assembly factors become dislodged, but this occurs sequentially, not en bloc. Eventually, the primordial pre-40 S emerges, still retaining some 90 S factors including Dhr1, now ready to unwind the final small nucleolar U3–18 S RNA hybrid. Our data shed light on the elusive 90 S to pre-40 S transition and clarify the principles of assembly and remodeling of large ribonucleoproteins.
Type of Medium:
Online Resource
ISSN:
0036-8075
,
1095-9203
DOI:
10.1126/science.abb4119
Language:
English
Publisher:
American Association for the Advancement of Science (AAAS)
Publication Date:
2020
detail.hit.zdb_id:
128410-1
detail.hit.zdb_id:
2066996-3
detail.hit.zdb_id:
2060783-0
SSG:
11
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