U2 small nuclear ribonucleoprotein particle (snRNP) auxiliary factor of 65 kDa, U2AF(65), can promote U1 snRNP recruitment to 5 ' splice sites

摘要

The splicing factor U2AF(65) , U2 small nuclear ribonucleoprotein particle (snRNP) auxiliary factor of 65 kDa, binds to pyrimidine-rich sequences at 3' splice sites to recruit U2 snRNP to premRNAs. We report that U2AF 15 can also promote the recruitment of U I snRNP to weak 5' splice sites that are followed by uridine-rich sequences. The arginine- and serine-rich domain of U2AF(65) is critical for U I recruitment, and we discuss the role of its RNA-RNA annealing activity in this novel function of U2AF(65). [References: 55]