hnRNP M interacts with PSF and p54(nrb) and co-localizes within defined nuclear structures.
The abundant heterogeneous nuclear ribonucleoprotein M (hnRNP M) is able to associate with early spliceosomes and to influence splicing patterns of specific pre-mRNAs. Here, by a combination of immunoprecipitation and pull-down assays, we have identified PSF (polypyrimidine tract-binding protein-associated splicing factor) and p54(nrb), two highly related proteins involved in transcription and RNA processing, as new binding partners of hnRNP M. HnRNP M was found to co-localize with PSF within a subset of nuclear paraspeckles and to largely co-fractionate with PSF and p54(nrb) in biochemical nuclear matrix preparations. In cells transfected with an alternatively spliced preprotachykinin (PPT) minigene expression of hnRNP M promoted exon skipping while expression of PSF favours exon inclusion. The latter effect was reverted specifically by co-expressing the full length hnRNP M or a deletion mutant capable of interaction with PSF and p54(nrb). Together our data provide new insights and some functional implications on the hnRNP M network of interactions.
Marko
Marija
M
RNA Processing Laboratory, Institute of Biological Research and Biotechnology, National Hellenic Research Foundation, 48 Vas. Constantinou Avenue, 11635 Athens, Greece.
Leichter
Michael
M
Patrinou-Georgoula
Meropi
M
Guialis
Apostolia
A
D017398:Alternative Splicing / Q000235:genetics; D002457:Cell Extracts; D002458:Cell Fractionation; D022003:Cell Nucleus Structures / Q000378:metabolism*; D004268:DNA-Binding Proteins; D005091:Exons / Q000235:genetics; D034761:Heterogeneous-Nuclear Ribonucleoprotein Group M / Q000378:metabolism*; D006801:Humans; D015530:Nuclear Matrix / Q000378:metabolism; D034521:Nuclear Matrix-Associated Proteins / Q000378:metabolism*; D050810:Octamer Transcription Factors / Q000378:metabolism*; D000072670:PTB-Associated Splicing Factor; D011485:Protein Binding; D011498:Protein Precursors / Q000235:genetics; D016601:RNA-Binding Proteins / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D015320:Tachykinins / Q000235:genetics
D002457:Cell Extracts; D004268:DNA-Binding Proteins; D034761:Heterogeneous-Nuclear Ribonucleoprotein Group M; C083214:NONO protein, human; D034521:Nuclear Matrix-Associated Proteins; D050810:Octamer Transcription Factors; D000072670:PTB-Associated Splicing Factor; D011498:Protein Precursors; D016601:RNA-Binding Proteins; D011994:Recombinant Proteins; D015320:Tachykinins; C044206:preprotachykinin