The biochemical defects of prp4-1 and prp6-1 yeast splicing mutants reveal that the PRP6 protein is required for the accumulation of the [U4/U6.U5] tri-snRNP.
We have raised specific antibodies against the PRP6 protein and shown that the U4, U5 and U6 snRNAs are co-precipitated with this protein. Using splicing extracts prepared from in vivo heat-inactivated cells, we have characterized the prp4-1 and prp6-1 biochemical defects. In inactivated prp4-1 cell extracts, the U6 snRNA content as well as the U6, U4/U6 snRNPs and the [U4/U6.U5] tri-snRNP particles amounts are severely reduced. In inactivated prp6-1 cell extracts, the PRP6 mutant protein is barely detectable. Glycerol gradient analyses indicate that, in these extracts, the [U4/U6.U5] tri-snRNPs are present in very low amounts, but U4/U6 snRNP particles are normally represented. These results establish that the PRP6 protein is required for the accumulation of the [U4/U6.U5] tri-snRNP. We found no evidence for the presence of the PRP6 protein in the U4/U6 particle.
Galisson
F
F
Département de Biologie Moléculaire, Institut Pasteur, Paris, France.
Legrain
P
P
D002499:Centrifugation, Density Gradient; D005656:Fungal Proteins; D005990:Glycerol; D009154:Mutation; D011233:Precipitin Tests; D012326:RNA Splicing / Q000235:genetics*; D017414:Ribonucleoprotein, U4-U6 Small Nuclear / Q000378:metabolism; D017415:Ribonucleoprotein, U5 Small Nuclear / Q000378:metabolism; D012441:Saccharomyces cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D017381:Spliceosomes / Q000378:metabolism*
D005656:Fungal Proteins; C065573:PRP6 protein, S cerevisiae; D017414:Ribonucleoprotein, U4-U6 Small Nuclear; D017415:Ribonucleoprotein, U5 Small Nuclear; D029701:Saccharomyces cerevisiae Proteins; D005990:Glycerol