鸳鸯鸭恒定链两异构体组织转录模式研究

Research on Tissue Transcription Patterns of Two Invariant Chain Isoforms of Muscovy Duck(Cairina moschata)

为探索鸳鸯鸭恒定链(MDIi)两种异构体MDIi-1和MDIi-2在不同组织或器官中的转录模式,建立了检测MDIi-1和MDIi-2组织转录的实时相对定量PCR方法,检测并分析了MDIi-1和MDIi-2在不同组织或器官中的转录特点。结果显示MDIi-1在法氏囊底部的转录水平为各组织或器官中最低(设为校正器);和校正器比较,MDIi-1在脾和小肠黏膜呈最高水平转录,而法氏囊颈部、肝、肾、胸腺和血液也呈较高水平转录,其他器官均低水平转录;MDIi-2在脾、法氏囊颈部和小肠黏膜也呈超过校正器的高水平转录,胸腺、肺和肾的转录水平仅略低于校正器,其他组织或器官转录水平都远低于校正器,呈极低水平转录。同一组织或器官中MDIi-1转录水平远高于MDIi-2,但MDIi-1和MDIi-2在所有被检组织或器官中转录具有很高的相关性,相关性系数达0.850 7。MDIi-1和MDIi-2共转录于所有被检组织或器官中,每一组织或器官中MDIi-1是主要转录形式,在所有被检组织或器官中两异构体均高转录于具有免疫防御功能的器官或组织,MDIi-1和MDIi-2差异性转录的试验结果为后续两异构体功能机制和基于MDIi的基因疫苗研究提供了基础资料。

Invariant chain(Ii),as a chaperone of MHC Ⅱ,plays an important role in antigen presentation by promoting MHC Ⅱ to maturate,capture antigen and guide antigen presentation in vertebrates.Ii isoforms containing a thyroglobulin-like domain(Tg domain)are also expressed by a single Ii gene through alternative splicing transcription.Ii isoforms with Tg domain involve in regulating the antigen presentation of MHC class Ⅱ molecule.The research on function and mechanism of Ii isoforms is more in-depth in mammals.But the main form,expression level and the functional relationship of Ii isoforms in tissues of birds including muscovy duck(Cairina moschata)are not fully clear.The Ii of muscovy duck(MDIi)has two isoforms.To explore the tissue expression patterns of two Ii isoforms of Muscovy duck,the real-time relative quantitative PCR(RQ-PCR)assay was established to detect the transcription levels of MDIi-1and MDIi-2and the transcription characteristics of MDIi-1and MDIi-2were compared in variant tissues or organs.Results showed that the lowest transcription level of MDIi 1was shown in bursa fundus,therefore used as calibrator.Compared with calibrator,MDIi-1was found at the highest transcription levels in spleen and intestinal mucosa,and the secondary highest ones in bursa stipe,liver,kidney,thymus,and blood.The rest organs transcribed MDIi-1at very low levels.For MDIi-2,spleen,bursa stipe,and intestinal mucosa transcribed MDIi-2at highest levels over the calibrator.The MDIi-2transcription levels in thymus,lung,and kidney were slightly lower than the calibrator.The MDIi-2transcription levels of other tissues were far below the calibrator and that of bursa fundus also was the lowest one.But MDIi-1was transcribed markedly higher than MDIi-2in the same tissue or organs.However,the transcription of MDIi-1has a high correlation with the transcription of MDIi-2in all tested tissues or organs.The correlation coefficient is 0.850 7.Thus two invariant chain isoforms,MDIi-1and MDIi-2,were co-transcribed in all detected tissues or organs of Muscovy duck,while MDIi-1was the main form of MDIi isorforms in each tissue or organs.MDIi-1and MDIi-2 were all high transcribed in the tissues or organs with immune defense functions among detected tissues.The differential transcription patterns of MDIi-1and MDIi-2in different tissues or organs of muscovy duck may provide the base for further research on MDIi function mechanism and gene vaccine based on MDIi in the future.