Thulasitha William Shanthakumar, Umasuthan Navaneethaiyer, Revathy Kasthuri Saranya, Whang Ilson, Lee Jehee
Department of Marine Life Sciences, School of Marine Biomedical Sciences, Jeju National University, Jeju Self-Governing Province 690-756, Republic of Korea; Fish Vaccine Development Center, Jeju National University, Jeju Self-Governing Province 690-756, Republic of Korea.
Department of Marine Life Sciences, School of Marine Biomedical Sciences, Jeju National University, Jeju Self-Governing Province 690-756, Republic of Korea.
Fish Shellfish Immunol. 2015 Jun;44(2):471-7. doi: 10.1016/j.fsi.2015.03.012. Epub 2015 Mar 18.
The CXC chemokine receptor 4 (CXCR4) is the cognate receptor of the CXC chemokine ligand 12 (CXCL12) and plays a pivotal role under immune-pathophysiological conditions. In the current study, the CXCR4 homolog of Oplegnathus fasciatus (OfCXCR4) was sequenced and the mRNA expression levels were characterized. The genomic structure of the cloned OfCXCR4 coding region (2094 bp) revealed a bi-exonic element, where the open reading frame (ORF) appears split by a single intron. Analysis of the ORF (1134 bp) of OfCXCR4 revealed a predicted protein of 42.1 kDa with typical seven transmembrane (TM) domain architecture and several conserved structural features, including two cysteine residues forming a predicted disulfide bond, a characteristic CXC motif (containing CYC) and a G-protein-coupled receptor (GPCR) family 1 signature. Furthermore, based on comparative analysis, the structure OfCXCR4 appears well conserved at both the genomic DNA and the amino acid levels. Phylogenic analysis of OfCXCR4 revealed that the greatest homology was with its teleostean relatives. Expression studies showed ubiquitous OfCXCR4 transcription, mainly in immune organs, with the highest levels in the head kidney. Examination of OfCXCR4 transcriptional regulation post injection to different stimuli or pathogens revealed a significant modulation of mRNA expression as detected by reverse transcription-quantitative real-time PCR. Evidence of various transcription factor binding sites present in the 5'-flanking region of OfCXCR4 coupled with its observed regulated mRNA expression suggest that it may have an important role in immune surveillance in rock bream.
CXC趋化因子受体4（CXCR4）是CXC趋化因子配体12（CXCL12）的同源受体，在免疫病理生理条件下起关键作用。在本研究中，对条石鲷的CXCR4同源物（OfCXCR4）进行了测序，并对其mRNA表达水平进行了表征。克隆的OfCXCR4编码区（2094 bp）的基因组结构显示为双外显子元件，其中开放阅读框（ORF）被一个内含子分开。对OfCXCR4的ORF（1134 bp）分析显示，预测的蛋白质为42.1 kDa，具有典型的七跨膜（TM）结构域结构和几个保守的结构特征，包括形成预测二硫键的两个半胱氨酸残基、一个特征性的CXC基序（包含CYC）和一个G蛋白偶联受体（GPCR）家族1特征。此外，基于比较分析，OfCXCR4的结构在基因组DNA和氨基酸水平上似乎都高度保守。OfCXCR4的系统发育分析表明，其与硬骨鱼亲属的同源性最高。表达研究表明OfCXCR4转录普遍存在，主要在免疫器官中，在头肾中的水平最高。对注射不同刺激物或病原体后OfCXCR4转录调控的研究表明，通过逆转录定量实时PCR检测到mRNA表达有显著调节。OfCXCR4 5'侧翼区域存在各种转录因子结合位点的证据及其观察到的mRNA表达调控表明，它可能在条石鲷的免疫监视中起重要作用。
