Inhibition of a spliceosome turnover pathway suppresses splicing defects

• DOI: 10.1073/pnas.0603188103
• Publication Date: 2006-09-01T00:38:00Z
• Authors: Shatakshi Pandit; Bert Lynn; Brian C. Rymond
• Keywords: Spliceosome; snRNP; Polypyrimidine tract

Defects in assembly are suggested to signal the dissociation of faulty splicing complexes. A yeast genetic screen was performed identify components putative discard pathway. Weak mutant alleles SPP382 (also called NTR1) were found suppress defects two proteins required for spliceosome activation, Prp38p and Prp8p. Spp382p is shown necessary cellular splicing, with premRNA and, some alleles, excised intron, accumulating after inactivation. Like spp382-1, a allele AAR2 identified this suppressor screen. Spp382p, Aar2p has reported role recycling complex recovered version spliceosomal core protein Possible insight into spp382 phenotype provided by observation that defective complexes lacking 5' exon cleavage intermediate tandem affinity purification-tagged Spp382 derivative. Stringent proteomic two-hybrid analyses show also interacts Cwc23p, DNA J-like present copurified Prp43p DExD/H-box ATPase. binds requires intron release from spliceosome. Consistent related function removal complexes, three prp43 mutants defects, efficiencies inversely proportionate measured ATPase activities. These data support existence Spp382p-dependent turnover pathway acting on spliceosomes.