Human RBMY regulates germline-specific splicing events by modulating the function of the serine/arginine-rich proteins 9G8 and Tra2-{beta}.
RBMY is a male germline RNA binding protein and potential alternative splicing regulator, but the lack of a convenient biological system has made its cellular functions elusive. We found that human RBMY fused to green fluorescent protein was strictly nuclear in transfected cells, but spatially enriched in areas around nuclear speckles with some components of the exon junction complex (EJC). Human RBMY (hRBMY) and the EJC components Magoh and Y14 also physically interacted but, unlike these two proteins, hRBMY protein did not shuttle to the cytoplasm. In addition, it relocalised into nucleolar caps after inhibition of RNA polymerase II transcription. Protein interactions were also detected between RBMY and splicing factors 9G8 and transformer-2 protein homolog beta (Tra2-beta), mediated by multiple regions of the RBMY protein that contain serine/arginine-rich dipeptides, but not by the single region lacking such dipeptides. These interactions modulated the splicing of several pre-mRNAs regulated by 9G8 and Tra2-beta. Importantly, ectopic expression of hRBMY stimulated the inclusion of a testis-enriched exon from the Acinus gene, whereas 9G8 and Tra2-beta repressed this exon. We propose that hRBMY associates with regions of the nucleus enriched in nascent RNA and participates in the regulation of specific splicing events in the germline by modulating the activity of constitutively expressed splicing factors.
Dreumont
Natacha
N
IGBMC Department of Functional Genomics, Illkirch, France.
Bourgeois
Cyril F
CF
Lejeune
Fabrice
F
Liu
Yilei
Y
Ehrmann
Ingrid E
IE
Elliott
David J
DJ
Stévenin
James
J
D017398:Alternative Splicing; D000818:Animals; D001120:Arginine; D006367:HeLa Cells; D006801:Humans; D008297:Male; D051379:Mice; D041681:NIH 3T3 Cells; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism*; D029543:Nucleocytoplasmic Transport Proteins / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D015202:Protein Engineering; D021381:Protein Transport; D012319:RNA Polymerase II / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D012694:Serine; D000068103:Serine-Arginine Splicing Factors; D013737:Testis / Q000166:cytology / Q000378:metabolism*; D015533:Transcriptional Activation
C491494:MAGOH protein, human; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D029543:Nucleocytoplasmic Transport Proteins; C406243:RBM8A protein, human; C501499:RBMY1A1 protein, human; D016601:RNA-Binding Proteins; C097083:TRA2B protein, human; D000068103:Serine-Arginine Splicing Factors; D012694:Serine; D001120:Arginine; D012319:RNA Polymerase II