A functional interaction between the survival motor neuron complex and RNA polymerase II.
The survival motor neuron (SMN) protein, the protein product of the spinal muscular atrophy (SMA) disease gene, plays a role in the assembly and regeneration of small nuclear ribonucleoproteins (snRNPs) and spliceosomes. By nanoelectrospray mass spectrometry, we identified RNA helicase A (RHA) as an SMN complex-associated protein. RHA is a DEAH box RNA helicase which binds RNA polymerase II (pol II) and reportedly functions in transcription. SMN interacts with RHA in vitro, and this interaction is impaired in mutant SMNs found in SMA patients. Coimmunoprecipitation demonstrated that the SMN complex is associated with pol II, snRNPs, and RHA in vivo. In vitro experiments suggest that RHA mediates the association of SMN with the COOH-terminal domain of pol II. Moreover, transfection of cells with a dominant negative mutant of SMN, SMNDeltaN27, causes accumulation of pol II, snRNPs, and RHA in nuclear structures that contain the known markers of gems and coiled bodies, and inhibits RNA pol I and pol II transcription in vivo. These findings indicate a functional as well as physical association of the SMN complex with pol II and suggest a role for the SMN complex in the assembly of the pol II transcription/processing machinery.
Pellizzoni
L
L
Howard Hughes Medical Institute, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA.
Charroux
B
B
Rappsilber
J
J
Mann
M
M
Dreyfuss
G
G
D000818:Animals; D017362:Cyclic AMP Response Element-Binding Protein; D004268:DNA-Binding Proteins / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D020365:RNA Helicases / Q000378:metabolism; D012319:RNA Polymerase II / Q000378:metabolism*; D012322:RNA Precursors / Q000378:metabolism; D012323:RNA Processing, Post-Transcriptional; D016601:RNA-Binding Proteins; D017411:Ribonucleoproteins, Small Nuclear / Q000378:metabolism; D055532:SMN Complex Proteins; D035181:TATA-Box Binding Protein; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic
D017362:Cyclic AMP Response Element-Binding Protein; D004268:DNA-Binding Proteins; D009419:Nerve Tissue Proteins; D012322:RNA Precursors; D016601:RNA-Binding Proteins; D017411:Ribonucleoproteins, Small Nuclear; D055532:SMN Complex Proteins; D035181:TATA-Box Binding Protein; D014157:Transcription Factors; D012319:RNA Polymerase II; D020365:RNA Helicases