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R Brosi

Publications and source records attributed to R Brosi.

4 recordsLinked to original sources
PubMed1994

Splicing factor SF3a60 is the mammalian homologue of PRP9 of S.cerevisiae: the conserved zinc finger-like motif is functionally exchangeable in vivo.

A cDNA encoding the 60 kDa subunit of mammalian splicing factor SF3a has been isolated. The deduced protein sequence reveals a 30% identity to the PRP9 splicing protein of the yeast S.cerevisiae. The highest homology is present in a zinc finger-like region in the C-terminal domain of both proteins. The PRP9 zinc finger-like motif has been replaced by the equivalent region of mammalian SF3a60. The chimeric protein rescues the temperature-sensitive phenotype of the prp9-1 mutant strain demonstrating that not only the structure but also the function of this domain has been conserved during evolution.

Amino Acid Sequence↗
PubMed1993

Interaction of mammalian splicing factor SF3a with U2 snRNP and relation of its 60-kD subunit to yeast PRP9.

In the assembly of a prespliceosome, U2 small nuclear ribonucleoprotein (snRNP) functions in pre-messenger RNA (mRNA) splicing together with splicing factors (SFs) 3a, SF3b, and several other proteins. The 17S but not the 12S form of U2 snRNP is active in splicing-complex formation. Here it is shown that the SF3a subunits correspond to three of the 17S U2 snRNP-specific polypeptides. SF3a interacts with U2 snRNP in the presence of SF3b to generate a structure similar to 17S U2 snRNP, which suggests a function for SF3a and SF3b in the incorporation of U2 snRNP into the spliceosome. Furthermore, the 60-kilodalton subunit of SF3a is related to the yeast splicing protein PRP9.

Adenosine Triphosphate↗
PubMed1993

Separation of splicing factor SF3 into two components and purification of SF3a activity.

Components required for the splicing of nuclear messenger RNA precursors in vitro have been isolated from HeLa cells. Here we describe the separation of splicing factor SF3 into two components, SF3a and SF3b. Both activities are required together with several other protein factors and U1 and U2 small nuclear ribonucleoproteins for the assembly of a presplicing complex which represents the first ATP-dependent step in the assembly of the active spliceosome. SF3a has been purified to homogeneity by a combination of ion-exchange chromatography, gel filtration, and glycerol gradient sedimentation. It consists of a complex of three polypeptides of 60, 66, and 120 kDa. The association of SF3a activity with these polypeptides has been confirmed by immunoprecipitation and depletion experiments using a monoclonal antibody directed against the 66-kDa subunit.

Blotting, Western↗