Sequence Variation And Expression Characteristic In Special Tissues Of HMGR In Goose

3-Hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) is a essential enzyme in cholesterol synthesis, and it plays an important role in the homeostasis of cholesterol. In the study, with the experiment objects of Landes goose and Sichuan white goose, The HMGR gene sequences of goose were analized, and the structure characteristics of active site in catalytic domain of goose HMGR gene were discussed; The expression characteristic of HMGR gene in geese were studied with RT-PCR method. The influence of force-feeding on the expression of HMGR gene in geese liver and its possible mechanism were analized. The results were as following:1. The partial catalytic domain mRNA sequences of Landes goose and Sichuan white goose were obtained, and it was completely identical in the two gene-types geese. The sequence identity of HMGR nucleotide sequence between goose, duck, chicken, human, mouse and hamster was 96%, 92%, 72%, 74%, 74%. The sequence identity of HMGR amino acid between goose,duck and chicken was all 97%. The nucleotide sequences coding glutamic acid in active site were fully uniform between chicken, duck, goose, human, mouse and hamster. The polymorphic sites of HMGR gene sequences of goose, duck and chicken were analysed. 35 variable sites were found, which were all Singleton variable sites, and nucleotide diversity was 0.02980.2. The mRNA expression of HMGR gene was detected in liver, abdominal and subcutaneous adipose tissues, intestines and muscles of Landes and Sichuan White geese, while it was highest in liver. These data suggested that cholesterol synthesis of the two gene-types geese was the same as chicken and human, and it was mainly synthesized in the liver not in adipose tissue.3. Overfeeding induced the striking change of plasma density of Insulin, Glucose and cholester, but there was interracial difference. In overfeeding group, the plasma Insulin concentration and the Cholesterol concentration in Sichuan White geese were markerly higher than in Landes. The Insulin concentration was positively correlated with the hepatic HMGR gene mRNA expression abundance in the two breeds (r=0.583, P＜0.05; r=0.597, P＜0.05). While the plasma cholesterol concentration was negtively correlated with the hepatic HMGR gene mRNA expression abundance (r=-0.559, P＜0.05; r=-0.562, P＜0.05). It indicated that Insulin and Cholesterol have major influence on hepatic HMGR gene mRNA expression.4. Overfeeding markedly depressed HMGR mRNA abundance in liver of the two breeds, and the degree of decrease to the Sichuan white geese is higher than to the Landes geese. The down-regulation of HMGR mRNA abundance may be caused by integrated regulation of Insulin, Glucose and Cholesterol.