Analysis On The Expression Characteristics Of CREB-H In Pigs And Its Correlation With The Expression Of ApoCⅡ

CREB-H is recently a liver-enriched transcription factor and plays a key role in maintaining lipid homeostasis by regulating the expression of the genes involved in hepatic lipid metabolic process. As a CREB-H target gene, ApoCⅡ activates LPL, and further contributes to the decomposition process of triglycerides. This experiment studied the molecular mechanism of CREB-H gene by using molecular biology experimental technique in the mRNA and protein molecular level.Meanwhile, the relationship of ApoC II mRNA and CREB-H as well as lipid metabolism was explored.The results were as follow.1. The relative mRNA and protein expression of CREB-H gene in different tissuses(heart, liver, spleen, lung, kidney, stomach, small intestine, cerebellum, hypothalamus, longissimus dorsi, psoas major and biceps femoris)of Mashen at 1-day old were determined by quantitative Real-time PCR and western bloting.The result indicated CREB-H mRNA mostly expressed in liver and intestine,while less in other tissuses;the expression of CREB-H protein in liver was higher than in other tissues, while CREB-H protein was not detected in heart,spleen and hypothalamus.The mRNA and protein expression of CREB-H in liver at seven stages of 1,30,60,90,120, 150, and 180-day old in Mashen and Large White pigs were determined by the same means. The result showed the relative mRNA and protein expression was highest at 1-day old, while as age i ncreased,the mRNA expression of CREB-H varied periodically, and the protein expression of CRE B-Hgradually decreased. In the same day, the protein expression of CREB-H of Mashen was signif-icantly higher than Large White. The results may provide the theory data for the regulatory mech anism of lipid metalism.2. Real-time PCR was used to determine the expression pattern of ApoC Ⅱ mRNA in 12 tissuses of Mashen pigs at 1-day old and developmental expression changes of ApoC Ⅱ mRNA in 7 stages. The result revealed ApoC Ⅱ specificity expressed in liver, and the ApoC Ⅱ mRNA expression in liver was affected by age and breed, was positively correlated with CREB-H, and could play an important role on lipid metabolism in pigs.3. Afte the treatment of liver passaged cells in Large White pigs with cAMP analogue (8Br-cAMP), the relative mRNA expression of CREB-H and ApoCⅡ was determined by quantitative Real-time PCR.The result showed CREB-H and ApoCⅡ expression levels rised, with the increase of the concentration of 8Br-cAMP. At the same time, the mRNA expression of CREB-H and ApoCⅡ increased and then decreased with prolongation of culture time under the induce of 1 mmol/L 8Br-cAMP, and significant positive correlation exsited between the two genes. This result can further reveal the mechanism of expression and regulation of CREB-H.