Structural investigation of Aquarius and associated splicing factors that couple pre-mRNA splicing to downstream RNA-processing events

• Applicant: Dr. Vladimir Pena, Ph.D.
• Subject Area: Structural Biology
• Term: from 2013 to 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 241796087

The spliceosome is a ribonucleoprotein machine that assembles on the pre mRNA and there catalyses the excision of introns and the ligation of exons. The entire splicing pathway is highly dynamic, with the spliceosome undergoing numerous remodelling steps driven by the motor activity of RNA helicases. Apart from participating in splicing per se, some of the spliceosomal components play pivotal roles in coupling splicing to other events of RNA metabolism.Aquarius is a massive spliceosomal helicase which binds the intron at a precise location and couples splicing to the deposition of the exon-junction complex on the mRNA as well as to the formation of snoRNPs from intronic segments. The structure of Aquarius is largely unknown and the mechanism that it employs for coupling is not understood.Converging evidence suggests that Aquarius is recruited to the spliceosome as part of a pentameric complex that we denote IBC (intron-binding complex). Subsequently, Aquarius and the other IBC components remain stably integrated into the spliceosome until the final stages of the splicing pathway. Elucidating the mechanistic role of Aquarius and, implicitly, that of the IBC in coupling spliceosomal remodelling to the downstream RNA-processing events would be greatly advanced by their 3D characterisation at atomic resolution. Therefore, our main goals are the crystallisation and X ray structure determination of Aquarius, of its complex with RNA and of the entire IBC. The crystallographic studies will be complemented with biochemical and biophysical analyses, in isolation and in the context of the whole spliceosome.

• DFG Programme: Research Grants
• International Connection: United Kingdom