摘要
【目的】研究猪肉嫩度性状候选基因-半胱氨酸蛋白酶抑制素B(Cystatin B,CSTB)基因对肌肉宰后嫩化的作用,为研究嫩度性状的遗传机理提供理论基础。【方法】采用RT-PCR结合克隆测序的方法,从猪肌肉组织总RNA中克隆到猪CSTB基因cDNA序列,并推导出其编码的氨基酸序列。采用PCR-RFLP方法,分析了84头猪CSTB基因多态性及其与嫩度性状的关联性。【结果】CSTB基因开放阅读框全长294bp,编码98个氨基酸。同源性分析结果表明,猪与人、鼠、牛的CSTB基因cDNA编码区(CDS)同源性分别为81%、85%和89%,推测氨基酸序列同源性为83%、76%和85%。蛋白质结构同源建模分析表明,该蛋白与人、鼠Cystatin B类似,具有stefin类蛋白酶抑制剂的典型空间结构,包括5条平行的β-sheet和负责与被抑制酶结合的楔形边缘。在CSTB基因第二内含子内PvuⅡ酶切位点检测到了AA、AB和BB这3种基因型,关联性分析表明AA基因型个体的各项嫩度指标均极显著低于另2种基因型的个体(P<0.01),最大剪切力为5.11kg,硬度值为19.31kg·s、平均剪切力为3.26kg。【结论】CSTB基因在不同物种间具有较高同源性,猪CSTB基因多态性与猪肉嫩度性状显著相关。
[Objective] The effects of the porcine cystatin B （CSTB） gene on postmortem tenderization of pork were studied in order to understand genetic mechanism of tenderness traits. [Method] Utilizing technique of RT-PCR and sequencing, the nucleotide and deduced amino acid sequence of the porcine CSTB gene were obtained in this study. And the polymorphisms of porcine CSTB gene was detected in 84 pigs by PCR-RFLP. Based on the polymorphism detection, the influence of CSTB genotype on tenderness traits were analyzed. [Result] The open reading frames of the CSTB gene were 294bp in length （encoding 98 amino acids）. The nucleotide sequence identities of porcine CSTB Complete Coding Sequence （CDS） were 81%, 85% and 89% compared to that of human, rat, and bovine CSTB CDS, respectively. The deduced amino acid sequence identities of the porcine CSTB protein were 83%, 76%, and 85% compared to that of rat, human, and bovine CSTB proteins, respectively. The structure of CSTB protein predicted by homologous modelling was similar to the results observed previously in humans and mouse. The five-stranded antiparallel [3-sheet and the wedge shaped edge were found in the model structure. The genotype AA in CSTB gene PvulI locus had significantly lower shear force （5.11 kg）, toughness （19.31 kg.s） and mean shear force （3.26 kg） than genotype AB and BB （P〈0.01）. [Conclusion] These results indicated that the homology of CSTB was high between species. There were significant correlation between the polymorphisms of porcine CSTB gene and the tenderness traits.
出处
《中国农业科学》
CAS
CSCD
北大核心
2008年第7期2120-2127,共8页
Scientia Agricultura Sinica
基金
教育部"长江学者和创新团队发展计划"(IRT0555-6)
国家科技支撑计划课题(2007BAD51B03)
教育部高等学校博士学科点专项基金项目(20060626003)
四川省科技厅"十一五"畜禽育种攻关项目(2006-YZGG-15)
