猪Cathepsin B基因和Cystatin B基因mRNA表达的发育性变化及组织差异

Developmental Expression and Tissue Distribution of Porcine Cathepsin B and Cystatin B mRNA

【目的】研究猪肉嫩度性状候选基因-组织蛋白酶B(cathepsin B,CTSB)和半胱氨酸蛋白酶抑制素B(cystatin B,CSTB)在体内不同组织、不同发育阶段的表达变化规律,为研究嫩度性状的遗传调控机理提供依据。【方法】采用荧光探针RT-PCR,定量分析CTSB和CSTB mRNA在两个品种猪的多个组织、多个发育时间点的表达量。【结果】RT-PCR结果表明,CTSB和CSTB mRNA表达量最高的组织为肾脏,心肌和骨骼肌中表达丰度低,股四头肌CSTB mRNA表达量极显著高于背最长肌。CTSB mRNA表达量在0～5月龄长白猪和梅山猪背最长肌中表现出先升高后降低的变化趋势,梅山猪峰值出现较早,并在4月龄后再次出现急剧上升。CSTB mRNA表达量在梅山猪中表现出生初期较高,随后逐渐降低的表达模式,长白猪的表达模式则为出生后表达量急剧升高,2月龄达到峰值,随后逐渐降低。2品种猪背最长肌组织CTSB和CSTB mRNA表达量表现出显著正相关。【结论】CTSB和CSTB mRNA表达量受到组织、发育阶段和品种影响,2基因mRNA表达量呈显著正相关。

【Objective】 The tissue-and developmental-specific expression of cathepsin B（CTSB） and cystatin B（CSTB） mRNA transcripts in porcine were studied in order to understand the genetic mechanism of tenderness traits.【Method】 The expression of CTSB and CSTB mRNA in different tissues and different development phases were revealed by Taqman real-time PCR analyses.【Result】 In adult pigs,CTSB mRNA and CSTB mRNA expression were widely detected in many tissues.The highest level of expression occurred in kidney and the lowest were in myocardium and skeletal muscle,respectively.The quadriceps femoris muscle had significantly higher CSTB mRNA expression than m.longissimus dorsi muscle（P0.01）.The expression of CTSB mRNA in m.longissimus dorsi muscle increased first then decreased in 0-5-month-old of age of Landrace and Meishan pigs.The peak of expression occured earlier in Meishan than in Landrace.Continuously decreased expression patterns of CSTB mRNA were detected among different months in m.longissimus dorsi muscle of Meishan pig.And in Landrace pig the expression peaked at 2 months of age,then decreased.【Conclusion】 These results indicate that the expression of CTSB and CSTB mRNA are influenced by tissue,developmental phases and breed factors.There is a significant positive correlation between CTSB and CSTB mRNA expression.