Abstract
The SF1 protein recognizes the 3' regions of the introns during the initial stages in the formation of the spliceosome, but it is not necessary for the constitutive splicing of all premRNA in the cells. Thus, SF1 acts as an alternative splicing factor on a sub-set of cellular premRNAs. Somatic mutations in several genes related to the splicing process, including SF1 and SF3b, have recentl…