RT Journal Article
SR Electronic
T1 A systems view of spliceosomal assembly and branchpoints with iCLIP
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 353599
DO 10.1101/353599
A1 Michael Briese
A1 Nejc Haberman
A1 Christopher R. Sibley
A1 Anob M. Chakrabarti
A1 Zhen Wang
A1 Julian König
A1 David Perera
A1 Vihandha O. Wickramasinghe
A1 Ashok R. Venkitaraman
A1 Nicholas M. Luscombe
A1 Christopher W. Smith
A1 Tomaž Curk
A1 Jernej Ule
YR 2018
UL http://biorxiv.org/content/early/2018/12/24/353599.abstract
AB Studies of spliceosomal interactions are challenging due to their dynamic nature. Here we employed spliceosome iCLIP, which immunoprecipitates SmB along with snRNPs and auxiliary RNA binding proteins (RBPs), to map human spliceosome engagement with snRNAs and pre-mRNAs. This identified over 50,000 branchpoints (BPs) that have canonical sequence and structural features. Moreover, it revealed 7 binding peaks around BPs and splice sites, each precisely overlapping with binding profiles of specific splicing factors. We show how the binding patterns of these RBPs are affected by the position and strength of BPs. For example, strong or proximally located BPs preferentially bind SF3 rather than U2AF complex. Notably, these effects are partly neutralized during spliceosomal assembly in a way that depends on the core spliceosomal protein PRPF8. These insights exemplify spliceosome iCLIP as a broadly applicable method for transcriptomic studies of splicing mechanisms.