fungi, intron recognition, pre-mRNA splicing, Prp4 kinase, safeguarding mechanism, SR proteins
Recently, it has been shown that Prp4 kinase activity is required for splicing of introns displaying weak splice sites and branch sequences in Schizosaccharomyces pombe. This finding raised the question if this mechanism is conserved in fungi. Here we will present in a short overview the Prp4 kinase and the two serine/arginine-rich (SR) proteins, Srp1 and Srp2, in a subset of fungi and compare them to their human orthologues. Furthermore, we will discuss and suggest Prp4 kinase and the SR proteins as part of a safeguarding system which evolved in single cell organisms to recognize introns and served as a basis for the development of alternative splicing.