SUMO-1 transiently localizes to Cajal bodies in mammalian neurons.
Cajal bodies (CBs) are nuclear organelles involved in the maturation of small nuclear ribonucleoproteins required for the processing of pre-mRNAs. They concentrate coilin, splicing factors and the survival of motor neuron protein (SMN). By using immunocytochemistry and transfection experiments with GFP-SUMO-1, DsRed1-Ubc9, GFP-coilin and GFP-SMN constructs we demonstrate the presence of SUMO-1 and the SUMO conjugating enzyme (Ubc9) in a subset of CBs in undifferentiated neuron-like UR61 cells. Furthermore, SUMO-1 is transiently localized into neuronal CBs from adult nervous tissue in response to osmotic stress or inhibition of methyltransferase activity. SUMO-1-positive CBs contain coilin, SMN and small nuclear ribonucleoproteins, suggesting that they are functional CBs involved in pre-mRNA processing. Since coilin and SMN have several putative motifs of SUMO-1 modification, we suggest that the sumoylation of coilin and/or SMN might play a role in the molecular reorganization of CBs during the neuronal differentiation or stress-response.
Navascues
J
J
Departamento de Anatomia y Biologia Celular, Unidad de Biomedicina (C.S.I.C), Universidad de Cantabria, Santander, y Centro de Investigación Biomedica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Spain.
Bengoechea
R
R
Tapia
O
O
Casafont
I
I
Berciano
M T
MT
Lafarga
M
M
D000818:Animals; D020541:Coiled Bodies / Q000737:chemistry*; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism; D008780:Methyltransferases / Q000037:antagonists & inhibitors; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009474:Neurons / Q000737:chemistry; D009687:Nuclear Proteins / Q000378:metabolism; D009997:Osmotic Pressure; D016716:PC12 Cells; D016601:RNA-Binding Proteins / Q000378:metabolism; D051381:Rats; D055532:SMN Complex Proteins; D025842:SUMO-1 Protein / Q000032:analysis / Q000378:metabolism*; D055533:Survival of Motor Neuron 1 Protein; D044763:Ubiquitin-Conjugating Enzymes / Q000032:analysis; D000098843:Ubiquitin-Conjugating Enzyme UBC9
D017362:Cyclic AMP Response Element-Binding Protein; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D016601:RNA-Binding Proteins; D055532:SMN Complex Proteins; D025842:SUMO-1 Protein; C526473:Smn1 protein, rat; D055533:Survival of Motor Neuron 1 Protein; C068921:p80-coilin; D008780:Methyltransferases; D044763:Ubiquitin-Conjugating Enzymes; D000098843:Ubiquitin-Conjugating Enzyme UBC9