The primary objective of this study is to document the transcriptional silencing of ALOX15, LTA4H, PIK3CA, PIK3CG, MAP2K6, PTGS1 and SYK genes in mature DCs. Specific aims were as follows. 1) Characterize the reduction in expression of these genes over time in DCs exposed to different maturation inducing stimuli, at the mRNA and protein levels. 2) Study the potential conservation of their transcriptional repression in several subtypes of mouse DCs. 3) Gain insight into the mechanism responsible for transcriptional silencing by evaluating epigenetic regulation and transcription factor binding to the promoter regions of these genes.