摘要
为研究鲟鱼主要组织相容性复合体(Major histocompatibility complex,MHC)基因的分子特征和表达,利用RACE技术克隆获得了西伯利亚鲟Acipernser baerii MHCⅡβ cDNA序列1443 bp,包括开放阅读框(OFR)801 bp,编码184个氨基酸。Blast分析显示,由MHCⅡβcDNA基因推导的氨基酸序列同其他物种的一致性为46%~83%,通过Smart站点分析,该序列具有SMART MHC_Ⅱ_beta结构域、SMART IGc1结构域和跨膜螺旋结构域;实时定量分析表明,正常情况下MHCⅡβ mRNA在西伯利亚鲟10种组织中均有表达,其中脾、头肾和血液中表达量较高,皮肤和肉中表达量极低(P<0.05);感染维氏气单胞菌Aeromonas veronii 40 h后,脾脏中MHCⅡβ mRNA的表达量显著低于未感染的对照组(P<0.05),直至93 h时恢复至对照组水平且有显著性变化(P<0.05)。研究表明,MHCⅡβ基因参与了西伯利亚鲟的免疫反应。
In this study,major histocompatibility(MHC)Ⅱβ cDNA was cloned from Siberian sturgeon Acipenser baerii by RACE. Sequence comparison indicated that the deduced amino acid sequence with 1443 bp including 801 bp open reading frame deducing 184 amino acids had 46%-83% identity with those of other species. The smart sequence analysis revealed that it had signal peptide, SMART MHC_Ⅱ_beta domain, SMART ⅠGc1 domain and transmembrane helix region. Real-time quantitative RT-PCR indicated that the MHCⅡβ was ubiquitously expressed in ten normal tissues including skin, meat, heart, gill, liver, spleen, intestine, kidney, brain and blood, higher in spleen,kindy and blood, and lower in liver, heart, intestine and brain,and nearly no in muscle and skin. There was significantly lower MHC Ⅱβ expression in spleen of the Siberian sturgeon challenged with bacterium Aeromonas veronii for 40 h than that in the control fish(P<0.05), recover to normal level in 96 h, indicating that MHCⅡβ is involved in the immunity of Sibreian sturgeon.
引文
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