Transcriptional regulatory network analysis of the over-expressed genes in adipose tissue

Adipose tissue plays important roles in whole body energy homeostasis and is now known to be a very important and active endocrine organ. The transcriptional regulatory network of adipose tissue metabolism is complex and much yet to be known. To identify transcriptional profile in adipose tissue, expressed sequence tag (EST) analysis using Digital Differential Display (DDD) was employed. The results of EST analysis were re-evaluated by microarray data using COXPRESdb (an available expression data repository). To uncover transcriptional regulatory mechanisms which play key roles in the adipose tissue metabolism, transcriptional regulatory network analysis was applied, using the promoter analysis and interaction network toolset. Sixty-five transcripts were found to be more frequent in adipose tissue in comparison to the other tissues. COXPRESdb result showed that 62 % of the identified over-expressed genes in adipose tissue by DDD had expression level greater than 1 (in base 2 logarithm). Based on coincidence of regulatory sites, candidate TFs were identified including TFs that previously known to be involved in adipose tissue metabolism (SP1, KROX, STAT1, LRF, VDR, LXR, SRF and HIF1) and TFs, such as CKROX, ZF5, ETF, AP-2, AP-2alpha, PAX-5, SPZ1, RBPJ and CACD, that had not been recognized previously. This work yielded several TF candidates activating in adipose tissue metabolism. These findings open a new avenue for future research on promoter occupancy and TF perturbation.