» Articles » PMID: 38876504

Characterization of Cwc2, U6 SnRNA, and Prp8 Interactions Destabilized by Prp16 ATPase at the Transition Between the First and Second Steps of Splicing

Overview
Journal RNA
Specialty Molecular Biology
Date 2024 Jun 14
PMID 38876504
Authors
Affiliations
Soon will be listed here.
Abstract

The spliceosome performs two consecutive transesterification reactions using one catalytic center, thus requiring its rearrangement between the two catalytic steps of splicing. The Prp16 ATPase facilitates exit from the first-step conformation of the catalytic center by destabilizing some interactions important for catalysis. To better understand rearrangements within the catalytic center, we characterize factors that modulate the function of Prp16: Cwc2, N-terminal domain of Prp8, and U6-AACAAU region. Alleles of these factors were identified through genetic screens for mutants that correct defects of alleles. Several of the identified U6, , and alleles are located in close proximity of each other in cryo-EM structures of the spliceosomal catalytic conformations. Cwc2 and U6 interact with the intron sequences in the first step, but they do not seem to contribute to the stability of the second-step catalytic center. On the other hand, the N-terminal segment of Prp8 not only affects intron positioning for the first step, but it also makes important contacts in the proximity of the active site for both the first and second steps of splicing. By identifying interactions important for the stability of catalytic conformations, our genetic analyses indirectly inform us about features of the transition-state conformation of the spliceosome.

References
1.
Siliciano P, Guthrie C . 5' splice site selection in yeast: genetic alterations in base-pairing with U1 reveal additional requirements. Genes Dev. 1988; 2(10):1258-67. DOI: 10.1101/gad.2.10.1258. View

2.
Collins C, Guthrie C . Genetic interactions between the 5' and 3' splice site consensus sequences and U6 snRNA during the second catalytic step of pre-mRNA splicing. RNA. 2002; 7(12):1845-54. PMC: 1370222. View

3.
Lardelli R, Thompson J, Yates 3rd J, Stevens S . Release of SF3 from the intron branchpoint activates the first step of pre-mRNA splicing. RNA. 2010; 16(3):516-28. PMC: 2822917. DOI: 10.1261/rna.2030510. View

4.
Schwer B, Guthrie C . PRP16 is an RNA-dependent ATPase that interacts transiently with the spliceosome. Nature. 1991; 349(6309):494-9. DOI: 10.1038/349494a0. View

5.
Hotz H, Schwer B . Mutational analysis of the yeast DEAH-box splicing factor Prp16. Genetics. 1998; 149(2):807-15. PMC: 1460209. DOI: 10.1093/genetics/149.2.807. View