Molecular cloning and bioactivity of an IL-2 homologue in large yellow croaker (Larimichthys crocea)
Molecular cloning and bioactivity of an IL-2 homologue in large yellow croaker (Larimichthys crocea)
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大黄鱼 (Larimichthys crocea) IL-2 同源物的分子克隆和生物活性
DOI：
10.1016/j.fsi.2018.07.040
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发表时间：
2018-10-01
影响因子：
4.7
通讯作者：
Chen, Xinhua
中科院分区：
文献类型：
--
作者：
Mu, Pengfei;Wang, Yuhua;Chen, Xinhua
白细胞介素2(IL-2)是一种重要的免疫调节细胞因子，在促进T细胞的增殖、活化和分化中起着至关重要的作用。本研究采用RACE-PCR技术克隆了大黄鱼IL-2同源物(LCIL-2)的全长基因。LCIL-2基因的开放阅读框(ORF)全长426个碱基，编码141个氨基酸的前体蛋白，包括一个20个氨基酸的信号肽和一个121个氨基酸的成熟肽，在ASN(77)和ASN(101)有两个可能的N-糖基化位点。LCIL-2在脾和血液等淋巴细胞丰富的组织中优先表达，在三价灭活细菌疫苗或Poly(I：C)刺激下，头肾和脾中表达增加。头肾原代白细胞(PKL)、头肾巨噬细胞(P1(M))和头肾粒细胞(PKG)也可检测到LCIL-2的表达，以头肾白细胞(PKL)表达最强。此外，脂多糖或聚(I：C)可轻度诱导PKL中LCIL-2的表达，而PHA或Con-A可显著诱导PKL中LCIL-2的表达。在毕赤酵母中表达的重组LCIL-2蛋白可以促进Th1(IL-2、干扰素-γ和T-bet)和Th2(IL-4/13A、IL-4/13B和GATA3)发育和分化相关基因以及IL-2下游转录因子STAT5B基因的表达，但抑制Th17(IL-17A/F2和IL-17A/F3)发育和分化相关基因的表达。综上所述，我们的结果表明，LCIL-2具有与其他脊椎动物IL-2相似的结构和功能特征，可能在T细胞的发育和分化中发挥作用。
Interleukin-2 (IL-2), an important immunomodulatory cytokine, plays a crucial role in promoting the proliferation, activation and differentiation of T cells. Here, the cDNA of an IL-2 homologue (LcIL-2) in large yellow croaker (Larimichthys crocea) was cloned by RACE-PCR techniques. The open reading frame (ORF) of LcIL-2 gene is 426 bp long and encoded a precursor protein of 141 amino acids (aa), with a 20-aa signal peptide and a 121-aa mature peptide containing two putative N-glycosylation sites at Asn(77) and Asn(101). The LcIL-2 is preferentially expressed in lymphocytes-rich tissues, such as spleen and blood, and is increased in head kidney and spleen upon inactivated trivalent bacterial vaccine or poly(I:C) stimulation. LcIL-2 expression could also be detected in primary head kidney leukocytes (PKL), primary head kidney macrophages (P1(M) and primary head kidney granulocytes (PKG), with the highest level in PKL. In addition, the expression level of LcIL-2 in PKL was slightly induced by LPS or poly(I:C), while markedly induced by PHA or Con-A. The recombinant LcIL-2 protein produced in Pichia pastoris could increase the expression of genes involved in Thl (IL-2, IFN-gamma and T-bet) and Th2 (IL-4/13A, IL-4/13B and GATA3) development and differentiation, and of the IL-2 downstream transcription factor STAT5B gene, but inhibit the expression of genes related to Th17 (IL-17A/F2 and IL-17A/F3) development and differentiation. Taken together, our results indicated that LcIL-2 possesses similar structural and functional characteristics to other vertebrate IL-2s, and may play a role in T cell development and differentiation.