Study of the effect of protein post-translacional modifications regarding the splicing regulation in Saccharomyces cerevisae

• Grant number: 13/22273-9
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• Start date: May 01, 2014
• End date: June 30, 2018
• Field of knowledge: Biological Sciences - Biochemistry - Molecular Biology
• Principal Investigator: Carla Columbano de Oliveira
• Grantee: Maria Griselda Perona
• Host Institution: Instituto de Química (IQ). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

In eukaryotes, most RNAs are transcribed as precursors that undergo different processing reactions in order for them to become mature and functional. One such process is the splicing, which involves the extraction of intronic regions and the ligation of neighboring exons. The splicing is performed by a nuclear complex named spliceosome, which is formed by RNAs, ribonucleoprotein complexes (RNPs) and approximately 90 proteins. The spliceosome is a very dynamic machinery that undergoes conformational changes, including structural and compositional rearrangements that are necessary for the catalytic reactions to take place. These conformational changes are promoted by RNA helicases of the DExD/H-box family, which are regulated by their interaction with other spliceosome components, or by posttranslational protein changes. Among the different posttranslational changes regulating the function of spliceosomal proteins is the ubiquination, which is has been identified based on the observation that many splicing factors are controlled by reversible ubiquination, making these factors attractive targets for studying the mechanisms responsible for the control of splicing. The protein Cwc24p was identified in a complex with the Saccharomyces cerevisiae splicing component NTC (NineTeen Complex), and later its interactions with the splicing proteins Prp19p and Brr2p were confirmed in vitro. Prp19p is the protein for which the NTC was named and Brr2p is a DExD/H-box helicase that interacts with the U5 snRNP. These interactions suggest a role for Cwc24p in the spliceosome activation. The aim of this work is the characterization of the molecular role of Cwc24p in splicing, analyzing how reversible protein modifications may regulate the activity of this protein and others with which it interacts during splicing. (AU)