Yu Yundong, Qiu Limei, Song Linsheng, Zhao Jianmin, Ni Duojiao, Zhang Ying, Xu Wei
Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Rd., Qingdao, Shandong 266071, China.
Fish Shellfish Immunol. 2007 Aug;23(2):419-29. doi: 10.1016/j.fsi.2006.12.004. Epub 2006 Dec 16.
LPS-induced TNF-alpha factor (LITAF) is a novel transcriptional factor that was first discovered in LPS-stimulated human macrophage cell line THP-1. LITAF can bind to TNF-alpha promoter to regulate its expression. The first scallop LITAF (named as CfLITAF) was cloned from Zhikong scallop Chlamys farreri by Expressed Sequence Tag (EST) and Polymerase Chain Reaction (PCR) techniques. The cDNA of CfLITAF was of 1240 bp and consisted of a 5' untranslated region (UTR) of 112 bp, a 3' UTR of 678 bp and an open reading frame (ORF) of 450 bp encoding a polypeptide of 149 amino acids with an estimated molecular mass of 16.08 kDa and theoretical isoelectric point of 6.77. A typical conserved LITAF-domain was identified in CfLITAF by SMART analysis. Homology analysis of the deduced amino acid sequence of CfLITAF with other known sequences by using the BLAST program revealed that CfLITAF was homologous to the LITAF from human and rat (Identity = 46%), cattle, horse, mouse and chicken (Identity = 48%), western clawed frog (Identity=42%), and zebrafish (Identity = 50%). The mRNA expression of CfLITAF in different tissues including haemocytes, muscle, mantle, heart, gill and gonad, and the temporal expression in haemocytes challenged by LPS or peptidoglycan (PGN) were measured by Real-time RT-PCR. CfLITAF mRNA transcripts could be detected in all tissues examined and be up-regulated in haemocytes after LPS challenge. No significant changes were observed after PGN stimulation. All these data indicated the existence of LITAF in scallop and also provided clue on the presence of TNF-alpha-like molecules in invertebrates.
脂多糖诱导的肿瘤坏死因子-α因子（LITAF）是一种新型转录因子，最初在脂多糖刺激的人巨噬细胞系THP-1中被发现。LITAF可与肿瘤坏死因子-α启动子结合以调节其表达。首个扇贝LITAF（命名为CfLITAF）通过表达序列标签（EST）和聚合酶链反应（PCR）技术从栉孔扇贝中克隆得到。CfLITAF的cDNA为1240 bp，由112 bp的5'非翻译区（UTR）、678 bp的3'UTR和450 bp的开放阅读框（ORF）组成，编码一个由149个氨基酸组成的多肽，估计分子量为16.08 kDa，理论等电点为6.77。通过SMART分析在CfLITAF中鉴定出一个典型的保守LITAF结构域。利用BLAST程序对CfLITAF推导的氨基酸序列与其他已知序列进行同源性分析，结果显示CfLITAF与人、大鼠（同一性=46%）、牛、马、小鼠和鸡（同一性=48%）、西方爪蟾（同一性=42%）以及斑马鱼（同一性=50%）的LITAF同源。通过实时逆转录聚合酶链反应（Real-time RT-PCR）检测CfLITAF在血细胞、肌肉、外套膜、心脏、鳃和性腺等不同组织中的mRNA表达，以及在脂多糖或肽聚糖（PGN）刺激的血细胞中的时序表达。在所检测的所有组织中均能检测到CfLITAF的mRNA转录本，脂多糖刺激后血细胞中的转录本上调。PGN刺激后未观察到显著变化。所有这些数据表明扇贝中存在LITAF，也为无脊椎动物中存在肿瘤坏死因子-α样分子提供了线索。
