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The molecular mechanisms linking glucose metabolism with active transcription remain undercharacterized in mammalian cells. Using nuclear factor-KB (NF-KB) as a glucose-responsive transcription factor, we show that cells use the hexosamine biosynthesis pathway and O-linked ß-/V-acetylglucosamine (O-GIcNAc) transferase (OGT) to potentiate gene expression in response to tumor necrosis factor (TNF) or etoposide. Chromatin immunoprecipitation assays demonstrate that, upon induction, OGT localizes to NF-KB-regulated promoters to enhance RelA acetylation. Knockdown of OGT abolishes p300-mediated acetylation of RelA on K310, a posttransla-tional mark required for full NF-KB transcription. Mapping studies reveal T305 as an important residue required for attachment of the O-GlcNAc moiety on RelA. Furthermore, p300 fails to acetylate a full-length RelA(T305A) mutant, linking O-GIcNAc and acetylation events on NF-KB. Reconstitution of RelA null cells with the RelA(T305A) mutant illustrates the importance of this residue for NF-KB-dependent gene expression and cell survival. Our work provides evidence for a unique regulation where attachment of the O-GIcNAc moiety to RelA potentiates p300 acetylation and NF-KB transcription. [ABSTRACT FROM AUTHOR]

IL-10 is a key regulator of the immune system that critically determines health and disease. Its expression is finely tuned both at the transcriptional and posttranscriptional levels. Although the importance of posttranscriptional regulation of IL-10 has been previously shown, understanding the underlying mechanisms is still in its infancy. In this study, using a combination of bioinformatics and molecular approaches, we report that microRNA (hsa-miR-106a) regulates IL-10 expression. The hsa-miR-106a binding site in the 3′ UTR of IL10 has been identified by site-directed mutagenesis studies. Also, the involvement of transcription factors, Sp1 and Egr1, in the regulation of hsa-miR-106a expression and concomitant decrease in the IL-10 expression, has also been demonstrated. In summary, our results showed that IL-10 expression may be regulated by miR-106a, which is in turn transcriptionally regulated by Egr1 and Sp1. [ABSTRACT FROM AUTHOR]