Gene Regulatory Networks Of PPARs On Pourtry Lipid Metabolism

Modern selective breeding has been successful in improving growth rate and intramuscular fat deposition in recent years. But excessive fat deposition such as visceral and subcutaneous fat deposition has also accompanied these selective progresses. Currently, few report on the molecular mechanism of adipogenesis, particularly on transcriptional regulation, in poultry has been published,. In this research, comparative genomic and data mining methods were useed to study the PPARs transcriptional regulation on poultry lipid metabolism. The main results were described as the following:1.Three duck PPARγsiRNA expression plasmids were constructed to examine the effect of PPARγon adipogenesis in ducks. The results indicate that 3 siRNA of PPARγwere all able to effectively decrese the expression of PPAR Y and the expression level of adipocyte fatty acid-binding protein(FABP4) and lipoprotein lipase(LPL) were repressed when the expression of PPAR Y is inhibit in duck adipose tissue. Meanwhile, the weight of abdominal fat is decreased compared with the control at 21 and 35 d of age. However, the triglyceride levels in muscle and serum are not affected when the expression of PPAR Y is repressed. It was indicated that the PPARγwas involved in the regulation of the lipid metablism in duck and inhibition of the expression of PPARγat 15 d of age led an decreasing abdominal fat deposition in ducks.2. ARACNE, an informatic software using reverse-engineering algorithm, was used to construct PPARs interaction network and genomic binding regions of PPARs by using data from 362 chips. It showed from the PPARs sub-network that PPARa and PPARy mainly regulated genes encoding enzymes related with lipid catabolic metabolism, while PPARβregulated genes encoding enzymes related with both lipid anabolic and catabolic metabolism. Gene expression profiles of different tissues obtained from newly hatched (day 0) broiler indicated that PPARa and genes in its sub-network involved in fatty acid oxidation were predominantly expressed in the liver, but the expressions of PPARβand PPARy in liver were similar with the other tissues. The expressions of the genes in PPARs sub-network involved in fatty acid oxidation and gluconeogenesis were highest in liver followed by duodenum, breast muscle, and finally brain.3.Currently,208 QTLs were identified controlling abdominal fat in chicken in public database, including 142 controlling abdominal fat weight and 66 controlling abdominal fat percentages. In the study, ARACNE algorithm and 362 chicken affymetrix genome arrays were used to construct the regulatory network for abdominal fat QTLs. The results indicated that 199 TFs relate abdominal fat change.57 TFs related in the abdominal fat at 10 w and 18 TFs related in liver in lean and fat chicken. ESRRB is the most important regulatory factors for abdominal fat weight at 10 w. In chicken, FOXK2 is the common master regulator in the abdominal fat at lOw and liver. The function of transcription factors involved in all aspects, such as lipid and glucose metabolism, immune, disease, and cell divsion and so on.