Proto-oncoprotein TLS/FUS is associated to the nuclear matrix and complexed with splicing factors PTB, SRm160, and SR proteins.
TLS/FUS is a nucleic acid-binding protein whose N-terminal half functions as a transcriptional activator domain in fusion oncoproteins found in human leukemias and liposarcomas. Previous reports have suggested a role for TLS/FUS in transcription and splicing processes. Here we report the association of TLS/FUS with the nuclear matrix and investigate its role in splicing. Splicing of two pre-mRNAs was inhibited in a TLS/FUS-immunodepleted extract and could only be partly restored by addition of recombinant TLS/FUS or/and SR proteins, known interaction partners of TLS/FUS. The subsequent analysis of TLS/FUS immunoprecipitates revealed that, in addition to the SR proteins SC35 and SRp75, the splicing factor PTB (hnRNPI) and the splicing coactivator SRm160 are complexed with TLS/FUS, thus explaining the inability to restore splicing completely. Coimmunolocalization confirmed the nuclear matrix association and interaction of TLS/FUS with PTB, SR proteins, and SRm160. Our results suggest that the matrix protein TLS/FUS plays a role in spliceosome assembly.
Meissner
Michael
M
Institute of Cancer Research, Borschkegasse 8a, University of Vienna, A-1090 Vienna, Austria.
Lopato
Sergiy
S
Gotzmann
Josef
J
Sauermann
Georg
G
Barta
Andrea
A
D034961:Antigens, Nuclear / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D008856:Microscopy, Fluorescence; D015530:Nuclear Matrix / Q000737:chemistry*; D034521:Nuclear Matrix-Associated Proteins / Q000378:metabolism; D038941:Polypyrimidine Tract-Binding Protein / Q000378:metabolism; D011233:Precipitin Tests; D011485:Protein Binding; D011518:Proto-Oncogene Proteins / Q000378:metabolism / Q000502:physiology; D012326:RNA Splicing; D034702:RNA-Binding Protein FUS / Q000378:metabolism / Q000502:physiology*; D016601:RNA-Binding Proteins / Q000378:metabolism; D018271:Signal Recognition Particle / Q000378:metabolism; D017381:Spliceosomes / Q000378:metabolism
D034961:Antigens, Nuclear; D034521:Nuclear Matrix-Associated Proteins; D011518:Proto-Oncogene Proteins; D034702:RNA-Binding Protein FUS; D016601:RNA-Binding Proteins; C111710:SRRM1 protein, human; D018271:Signal Recognition Particle; D038941:Polypyrimidine Tract-Binding Protein