Shang Na, Sun Xiao-Feng, Hu Wei, Wang Ya-Ping, Guo Qiong-Lin
State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
Fish Shellfish Immunol. 2008 Apr;24(4):412-25. doi: 10.1016/j.fsi.2007.12.007. Epub 2007 Dec 23.
Partial cDNA sequences of TCRgamma and CD3gamma/delta were isolated from the thymus of common carp (Cyprinus carpio L.) by the method of suppression subtractive hybridization (SSH). Subsequently the full length cDNAs of carp TCRgamma and CD3gamma/delta were obtained by means of 3' RACE and 5' RACE, respectively. The full length of carp TCRgamma chain is 1368bp and encodes 326 amino acids including a signal peptide region of 19 amino acids and a transmembrane region of 23 amino acids at the C-terminal region from aa 291 to 313. The V region of carp TCRgamma contains 109 amino acids, the core motif FGXG in J segment was also found in carp TCRgamma. The C region of carp TCRgamma contains the characteristic CX6PX6WX45C motif. The CP region of carp TCR Cgamma contains 37 amino acids. The full length of carp CD3gamma/delta is 790bp and encodes 175 amino acids including a signal peptide region of 17 amino acids and a transmembrane region of 23 amino acids from aa 93 to 115. Similar to other known CD3gamma/deltas, four cysteine residues in the extracellular domain and an immunoreceptor tyrosine-based activation motif ITAM (YxxL/Ix6-8YxxL/I) in the intracellular domain are also included in carp CD3gamma/delta. Differing from other known CD3gamma/deltas, carp CD3gamma/delta lacks the CXXCXE motif in the extracellular domain. RT-PCR analysis demonstrated that the expression of TCRgamma gene was mainly in the thymus and gill of 6-month carp, but in 18-month carp, TCRgamma gene was detected in all the examined tissues. The expression of CD3gamma/delta gene was detected in all examined tissues of 6 and 18-month carp; among them, the highest expression level was in the thymus of 6-month carp. In situ hybridization showed that CD3gamma/delta-expressing cells were widely distributed in the head kidney, spleen and kidney of carp, whereas in the thymus, they were densely distributed in the lymphoid outer zone and scattered in the epithelioid inner zone.
通过抑制性消减杂交（SSH）方法，从鲤鱼（Cyprinus carpio L.）胸腺中分离出TCRγ和CD3γ/δ的部分cDNA序列。随后，分别通过3' RACE和5' RACE获得了鲤鱼TCRγ和CD3γ/δ的全长cDNA。鲤鱼TCRγ链全长1368bp，编码326个氨基酸，包括19个氨基酸的信号肽区域和C末端区域（从第291位氨基酸到313位氨基酸）23个氨基酸的跨膜区域。鲤鱼TCRγ的V区域包含109个氨基酸，在鲤鱼TCRγ中也发现了J片段中的核心基序FGXG。鲤鱼TCRγ的C区域包含特征性的CX6PX6WX45C基序。鲤鱼Cγ的CP区域包含37个氨基酸。鲤鱼CD3γ/δ全长790bp，编码175个氨基酸，包括17个氨基酸的信号肽区域和从第93位氨基酸到115位氨基酸的23个氨基酸的跨膜区域。与其他已知的CD3γ/δ相似，鲤鱼CD3γ/δ的胞外结构域中也包含四个半胱氨酸残基，胞内结构域中包含基于免疫受体酪氨酸的激活基序ITAM（YxxL/Ix6 - 8YxxL/I）。与其他已知的CD3γ/δ不同，鲤鱼CD3γ/δ在胞外结构域中缺少CXXCXE基序。RT-PCR分析表明，TCRγ基因在6个月龄鲤鱼的胸腺和鳃中表达为主，但在18个月龄鲤鱼中，在所有检测组织中均检测到TCRγ基因。在6个月龄和18个月龄鲤鱼的所有检测组织中均检测到CD3γ/δ基因表达；其中，6个月龄鲤鱼胸腺中的表达水平最高。原位杂交显示，表达CD3γ/δ的细胞广泛分布于鲤鱼的头肾、脾脏和肾脏中，而在胸腺中，它们密集分布于淋巴外区，散在于上皮样内区。
