The mechanism of somatic inhibition of Drosophila P-element pre-mRNA splicing: multiprotein complexes at an exon pseudo-5' splice site control U1 snRNP binding.

• DOI: 10.1101/gad.6.8.1386
• Publication Date: 2007-06-05T21:15:46Z
• Authors: C W Siebel; L D Fresco; D C Rio
• Keywords: snRNP; Splice site mutation; splice; Spliceosome

Somatic inhibition restricts splicing of the Drosophila P-element third intron (IVS3) to germ line. We have exploited this simple system provide a model for mechanism alternative pre-mRNA splicing. Biochemical complementation experiments revealed that somatic extracts inhibited U1 snRNP binding 5' splice site. Using sensitive RNase protection and modification-interference assays, we found bound pseudo-5' site in exon multiprotein complexes an adjacent Binding these factors appeared mediate inhibitory effect, because mutations sites blocked activated vitro. Likewise, wild-type, but not mutant, RNA titrated away from Thus, defined as crucial components regulatory element, correlated activity with specific cells, provided mechanistic description inhibition. Because involves general functions such protein recognition sequences changes distribution snRNP, our data may also insights into how are selected.