| Autor: |
Melchiorre, Mariangela, Miccoli, Sara, Renna, Lucia A., Cignarelli, Angelo, Caccioppoli, Cristina, Orlando, Maura R., De Stefano, Francesca, Natalicchio, Annalisa, Perrini, Sebastio, Laviola, Luigi, Giorgino, Francesco |
| Předmět: |
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| Zdroj: |
Diabetes; Jun2007 Supplement 1, Vol. 56, pA6-A6, 1/5p |
| Abstrakt: |
SUMO-ylation has emerged as a key modification step in regulating adipocyte transcription factors such as C/EBPα/β and PPARγ. The objective of this study was to explore the role of Ubc9, the only enzyme able to conjugate SUMO to other substrates, on adipocyte differentiation, using a siRNA-based strategy. Ubc9-specific siRNA reduced Ubc9 levels in 3T3-L1 preadipocytes of about 60% up to 3-4 days after exposure to the differentiation-inducing mixture. PPARTγ and C/EBPβ expression was markedly increased in control cells 2 to 6 days after the induction of differentiation. By contrast, the expression of these factors was delayed and significantly lower (p<0.05 at day 2 vs control) in Ubc9 siRNA-treated cells. Oil Red O staining demonstrated cell triglycerides as minute lipid droplets in only 30% of Ubc9-siRNA treated cells, as compared to larger droplets evident in 100% of control cells. To confirm the importance of Ubc9 in regulating adipogenesis, we next investigated the time-course and subcellular localization of this enzyme during the differentiation process. Ubc9 mRNA and protein levels peaked at day 2 (2.5 fold, p<0.05) and then gradually declined to basal levels at day 8. Ubc9 protein, revealed by immunoblotting of cellular fractions and immunofluorescence by confocal microscopy, was confined mostly in the nucleus of preadipocytes, whereas was localized also in specific cytoplasmic compartments, beginning on day 4 after differentiation induction, partially co-localizing with GLUT4. In conclusion, these results indicate that Ubc9 expression and localization is regulated during the differentiation process, and suggest that Ubc9 participates in adipogenesis at various stages of the differentiation program. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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