Structural insights into the cross-exon to cross-intron spliceosome switch.

ABSTRACT: Early spliceosome assembly can occur through an intron-defined pathway, whereby U1 and U2 small nuclear ribonucleoprotein particles (snRNPs) assemble across the intron¹. Alternatively, it can occur through an exon-defined pathway^2-5, whereby U2 binds the branch site located upstream of the defined exon and U1 snRNP interacts with the 5' splice site located directly downstream of it. The U4/U6.U5 tri-snRNP subsequently binds to produce a cross-intron (CI) or cross-exon (CE) pre-B complex, which is then converted to the spliceosomal B complex^6,7. Exon definition promotes the splicing of upstream introns^2,8,9 and plays a key part in alternative splicing regulation^10-16. However, the three-dimensional structure of exon-defined spliceosomal

SUBMITTER: Zhang Z 

PROVIDER: S-EPMC11208138 | biostudies-literature | 2024 Jun

REPOSITORIES: biostudies-literature