90S pre-ribosome transformation into the primordial 40S subunit

Cheng, Jingdong; Lau, Benjamin; La Venuta, Giuseppe; Ameismeier, Michael; Berninghausen, Otto; Hurt, Ed and Beckmann, Roland (2020): 90S pre-ribosome transformation into the primordial 40S subunit. In: Science, Vol. 369, No. 6510: pp. 1470-1476

Abstract

Production of small ribosomal subunits initially requires the formation of a 90S precursor followed by an enigmatic process of restructuring into the primordial pre-40S 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 90S pre-ribosome, followed by Utp24 endonuclease-driven RNA cleavage at site A(1), thereby separating the 5'-external transcribed spacer (ETS) from 18S ribosomal RNA. Next, the 5 '-ETS and 90S assembly factors become dislodged, but this occurs sequentially, not en bloc. Eventually, the primordial pre-40S emerges, still retaining some 90S factors including Dhr1, now ready to unwind the final small nucleolar U3-18S RNA hybrid. Our data shed light on the elusive 90S to pre-40S transition and clarify the principles of assembly and remodeling of large ribonucleoproteins.

• Item Type: Journal article
• Faculties: Chemistry and Pharmacy > Department of Biochemistry
• Subjects: 500 Science > 540 Chemistry
• ISSN: 0036-8075
• Language: English