GSE97203
U2AF65Prp2 promotes intron definition by stabilizing U1 snRNP at the 5' splice site
Prp2 (U2AF65) is an essential splicing factor, that recognizes the poly-Py track near the 3' SS.  We have previously observed that when Prp2 is inactivated using a prp2 temperature-sensitive allele, while most of the pre-mRNA is not processed, some are normally spliced.  This observation even more noticeable during meiosis, since pre-mRNA regulation is executed at different levels (splicing, polyadenylation and stability). Using RNAseq, we have determined genome-wide the splicing efficiency of fission yeast cells as they progress into synchronous meiosis, in the presence or absence of functional Prp2.  To our surprise, the main characteristic that defines if any given intron requires Prp2 to be spliced depends on the last nucleotides of the preceding exon, next to the 5' SS in the nucleotide that anneal with U1 RNA.  Thus, by simple genetic manipulation, we can modulate the dependency of any given intron on Prp2.  We propose that the role of Prp2 consist in the stabilization of a loop between the 5'SS and the 3' SS, which also depends on the annealing strength between U1 and the 5' SS. Overall design: Splicing profile of two samples of cells entering into meiosis I, comparing the effect of temperature-inactivation of Prp2-1 (U2AF65)