Members of a family of proteins (the RD family) detected by a U1 70K monoclonal antibody are present in spliceosomal complexes.

AUTOR(ES)

Staknis, D

RESUMO

We have characterized a monoclonal antibody (mAb) to the U1 snRNP component U1 70K. We find that this antibody recognizes several proteins, in addition to U1 70K, in purified spliceosomal complexes and in total HeLa cell nuclear extract preparations. The novel mAb U1 70K antigens can also be specifically immunoprecipitated by the antibody. Similarly to U1 70K, many of the mAb U1 70K antigens can be phosphorylated by a co-purifying kinase activity. The epitope recognized by mAb U1 70K was previously shown to be a repeating arginine/aspartate (RD) dipeptide. Thus we have designated the novel mAb U1 70K antigens the RD family. Comparison of mAb U1 70K with a recently characterized antibody, mAb 16H3, whose epitope is a repeating R/D or R/E motif, showed that a large subset of the antigens are common. In contrast, most of the mAb U1 70K antigens are distinct from the proteins detected by mAb 104, an antibody to the SR family of splicing factors.

Documentos Relacionados

• Structure and expression of a plant U1 snRNP 70K gene: alternative splicing of U1 snRNP 70K pre-mRNAs produces two different transcripts.
• The association of the U1-specific 70K and C proteins with U1 snRNPs is mediated in part by common U snRNP proteins.
• The yeast homolog of the U1 snRNP protein 70K is encoded by the SNP1 gene.
• The plant U1 small nuclear ribonucleoprotein particle 70K protein interacts with two novel serine/arginine-rich proteins.
• In vitro reconstitution of mammalian U1 snRNPs active in splicing: the U1-C protein enhances the formation of early (E) spliceosomal complexes.