Characterization of a new SUMO-1 nuclear body (SNB) enriched in pCREB, CBP, c-Jun in neuron-like UR61 cells.
The neuron-like UR61 cell is a stable PC12 subline that contains a mouse N-ras oncogene. Dexamethasone (Dex) treatment induces a neuron-like differentiation, which is associated with neuritogenesis and nuclear expression of the glucocorticoid receptor and c-Jun. In differentiated UR61 cells, small ubiquitin-like modifiers 1 (SUMO-1) is concentrated in a new category of SUMO-1 nuclear bodies (SNBs) distinct from promyelocytic leukemia (PML) bodies by their large size and absence of PML protein. SNBs are 1 to 3 mum in diameter and exhibit a fine granular texture by electron microscopy. They are free of splicing factors and transcription foci and show spatial associations with Cajal bodies. In addition to SUMO-1 and the E2-conjugating enzyme Ubc9, which is essential for sumoylation, SNBs concentrate the transcriptional regulators CBP, CREB, and c-Jun. Moreover, transfection experiments demonstrate that SNBs accumulate the active conjugating form of SUMO-1 but not the conjugation defective variant of SUMO-1, supporting that SNBs are sites of sumoylation. Our results suggest that SNBs play a role in the control of the nucleoplasmic concentration of transcription regulators involved in neuroprotection and survival of the UR61 cells.
Navascués
Joaquín
J
Division of Gene Regulation and Expression, Wellcome Trust Biocentre, University of Dundee, DD1 5EH, Dundee, UK.
Bengoechea
Rocio
R
Tapia
Olga
O
Vaqué
José P
JP
Lafarga
Miguel
M
Berciano
Maria T
MT
D000818:Animals; D050882:CREB-Binding Protein / Q000378:metabolism*; D002466:Cell Nucleolus / Q000378:metabolism / Q000648:ultrastructure; D002478:Cells, Cultured; D003907:Dexamethasone; D005786:Gene Expression Regulation; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009474:Neurons / Q000737:chemistry / Q000378:metabolism*; D016716:PC12 Cells; D051381:Rats; D025842:SUMO-1 Protein / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism
D025842:SUMO-1 Protein; D003907:Dexamethasone; D050882:CREB-Binding Protein; D048031:JNK Mitogen-Activated Protein Kinases