Symmetrical dimethylarginine methylation is required for the localization of SMN in Cajal bodies and pre-mRNA splicing.
The nuclear structures that contain symmetrical dimethylated arginine (sDMA)-modified proteins and the role of this posttranslational modification is unknown. Here we report that the Cajal body is a major epitope in HeLa cells for an sDMA-specific antibody and that coilin is an sDMA-containing protein as analyzed by using the sDMA-specific antibody and matrix-assisted laser desorption ionization time of flight mass spectrometry. The methylation inhibitor 5'-deoxy-5'-methylthioadenosine reduces the levels of coilin methylation and causes the appearance of SMN-positive gems. In cells devoid of Cajal bodies, such as primary fibroblasts, sDMA-containing proteins concentrated in speckles. Cells from a patient with spinal muscular atrophy, containing low levels of the methyl-binding protein SMN, localized sDMA-containing proteins in the nucleoplasm as a discrete granular pattern. Splicing reactions are efficiently inhibited by using the sDMA-specific antibody or by using hypomethylated nuclear extracts, showing that active spliceosomes contain sDMA polypeptides and suggesting that arginine methylation is important for efficient pre-mRNA splicing. Our findings support a model in which arginine methylation is important for the localization of coilin and SMN in Cajal bodies.
Boisvert
Francois-Michel
FM
Terry Fox Molecular Oncology Group, Lady Davis Institute for Medical Research, Sir Mortimer B. Davis Jewish General Hospital, Montréal, Québec, Canada H3T 1E2.
Cote
Jocelyn
J
Boulanger
Marie-Chloe
MC
Cleroux
Patrick
P
Bachand
Francois
F
Autexier
Chantal
C
Richard
Stephane
S
D000906:Antibodies / Q000378:metabolism; D001120:Arginine / Q000031:analogs & derivatives / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism; D020541:Coiled Bodies / Q000378:metabolism*; D004247:DNA / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D005347:Fibroblasts / Q000378:metabolism; D019084:Fluorescent Antibody Technique, Indirect; D006367:HeLa Cells; D006801:Humans; D013058:Mass Spectrometry; D008745:Methylation; D008856:Microscopy, Fluorescence; D009134:Muscular Atrophy, Spinal / Q000378:metabolism; D011233:Precipitin Tests; D012326:RNA Splicing; D012333:RNA, Messenger / Q000378:metabolism; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014162:Transfection
D000906:Antibodies; D012333:RNA, Messenger; D004247:DNA; D001120:Arginine