Proteomic analysis of the U1 snRNP of Schizosaccharomyces pombe reveals three essential organism-specific proteins.
Characterization of spliceosomal complexes in the fission yeast Schizosaccharomyces pombe revealed particles sedimenting in the range of 30-60S, exclusively containing U1 snRNA. Here, we report the tandem affinity purification (TAP) of U1-specific protein complexes. The components of the complexes were identified using (LC-MS/MS) mass spectrometry. The fission yeast U1 snRNP contains 16 proteins, including the 7 Sm snRNP core proteins. In both fission and budding yeast, the U1 snRNP contains 9 and 10 U1 specific proteins, respectively, whereas the U1 particle found in mammalian cells contains only 3. Among the U1-specific proteins in S. pombe, three are homolog to the mammalian and six to the budding yeast Saccharomyces cerevisiae U1-specific proteins, whereas three, called U1H, U1J and U1L, are proteins specific to S. pombe. Furthermore, we demonstrate that the homolog of U1-70K and the three proteins specific to S. pombe are essential for growth. We will discuss the differences between the U1 snRNPs with respect to the organism-specific proteins found in the two yeasts and the resulting effect it has on pre-mRNA splicing.
Newo
Alain N S
AN
Institute of Genetics, Technical University of Braunschweig, Spielmannstr. 7, 38106 Braunschweig, Germany.
Lützelberger
Martin
M
Bottner
Claudia A
CA
Wehland
Jürgen
J
Wissing
Josef
J
Jänsch
Lothar
L
Käufer
Norbert F
NF
D002846:Chromatography, Affinity; D040901:Proteomics; D017412:Ribonucleoprotein, U1 Small Nuclear / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*; D017411:Ribonucleoproteins, Small Nuclear / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*; D012568:Schizosaccharomyces / Q000235:genetics / Q000254:growth & development; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*; D017381:Spliceosomes / Q000737:chemistry; D053719:Tandem Mass Spectrometry
D017412:Ribonucleoprotein, U1 Small Nuclear; D017411:Ribonucleoproteins, Small Nuclear; D029702:Schizosaccharomyces pombe Proteins; C519198:U1H protein, S pombe; C519199:U1J protein, S pombe; C519200:U1L protein, S pombe