To gain insight into the genetic basis of inflammation, our laboratory has recently undertaken the identification of genes selectively expressed by DCs, a cell population known to play a major role in the control of inflammatory responses. Using a modified differential display strategy, we have identified a series of transcripts representing genes specifically upregulated in DCs. One of the transcripts has been found to represent the murine homolog of a bacterial gene coding for a nicotinamide phosphoribosyl transferase (NAmPRTase), an enzyme involved in NAD biosynthesis. We have recently demonstrated that similarly to its microbial counterpart, the murine protein is a NAmPRTase, catalyzing the condensation of nicotinamide with 5-phosphoribosyl-1-pyrophosphate to yield nicotinamide mononucleotide, an intermediate in the biosynthesis of Nicotinamide adenine dinucleotide (NAD). This observation led us to further explore the possible relationship between NAD metabolism and the control of immune responses. Nicotinamide adenine dinucleotide (NAD) has been known for several decades to play a major role as a coenzyme in numerous oxidation-reduction reactions. Recently, the distinct role of NAD as a precursor for molecules involved in regulatory processes has also been recognized. NAD can indeed serve as a substrate for covalent protein modification catalysed by enzymes identified as ADP-ribosyl transferases. During ADP ribosylation, the ADP-ribose moiety of NAD is enzymatically transferred onto an acceptor protein, a reaction known to profoundly affect the target protein effector function. Numerous proteins endowed with ADP-ribosyl tyransferase capacity have been identified in mammals including mono and poly (ADP-ribosyl) transferases (respectively mARTs and PARPs) and sirtuins. This novel class of NAD-dependent protein deacetylases is involved in gene and has recently attracted great interest following the demonstration that they may play a role in cell longevity in both yeast and C. elegans. Elevated expression of the NAmPRTase in cells of the innate immune system has led us to postulate an important role for NAD-dependent enzymes in the control of the inflammatory response, an hypothesis presently under investigation in our laboratory. [To gain insight into the genetic basis of inflammation, our laboratory has recently undertaken the identification of genes selectively expressed by DCs, a cell population known to play a major role in the control of inflammatory responses. Using a modified differential display strategy, we have identified a series of transcripts representing genes specifically upregulated in DCs. One of the transcripts has been found to represent the murine homolog of a bacterial gene coding for a nicotinamide phosphoribosyl transferase (NAmPRTase), an enzyme involved in NAD biosynthesis. We have recently demonstrated that similarly to its microbial counterpart, the murine protein is a NAmPRTase, catalyzing the condensation of nicotinamide with 5-phosphoribosyl-1-pyrophosphate to yield nicotinamide mononucleotide, an intermediate in the biosynthesis of Nicotinamide adenine dinucleotide (NAD). This observation led us to further explore the possible relationship between NAD metabolism and the control of immune responses. Nicotinamide adenine dinucleotide (NAD) has been known for several decades to play a major role as a coenzyme in numerous oxidation-reduction reactions. Recently, the distinct role of NAD as a precursor for molecules involved in regulatory processes has also been recognized. NAD can indeed serve as a substrate for covalent protein modification catalysed by enzymes identified as ADP-ribosyl transferases. During ADP ribosylation, the ADP-ribose moiety of NAD is enzymatically transferred onto an acceptor protein, a reaction known to profoundly affect the target protein effector function. Numerous proteins endowed with ADP-ribosyl tyransferase capacity have been identified in mammals including mono and poly (ADP-ribosyl) transferases (respectively mARTs and PARPs) and sirtuins. This novel class of NAD-dependent protein deacetylases is involved in gene and has recently attracted great interest following the demonstration that they may play a role in cell longevity in both yeast and C. elegans. Elevated expression of the NAmPRTase in cells of the innate immune system has led us to postulate an important role for NAD-dependent enzymes in the control of the inflammatory response, an hypothesis presently under investigation in our laboratory.]