Fan Bing-Lin, Zhu Wu-Ling, Zou Guo-Lin, Luo Guo-Sheng, Xu Chun-Lei, Zhao Wei-Xing
Department of Basic Medicine, Xinxiang Medical College, Xinxiang, Henan, 453003, PR China.
Ai Zheng. 2004 Mar;23(3):249-53.
BACKGROUND & OBJECTIVE: Abnormal expression of genes is related to development and progression of hepatocellular carcinoma (HCC); however, the detailed mechanism is unclear yet because the known genetic information is not sufficient at present. This study was to explore cloning and identification of fibrinogen gamma polypeptide (FGG) gene differentially expressed in human hepatocellular carcinoma.
The suppression subtractive hybridization was used to obtain subtracted cDNA products of HCC, then the products were cloned by T/A method. The differential expression of gene in HCC was identified by DNA sequencing analysis, Northern blot analysis, rapid amplification of cDNA end (RACE), and reverse transcription polymerase chain reaction (RT-PCR).
Firstly, a cDNA fragment of 787 nucleotides was screened from the subtracted cDNA clones, and it was further discovered that the expression of the cDNA fragment was higher significantly in human hepatocellular carcinoma cell strains of SMMC-7721 and HepG2 than in normal hepatocytes by Northern blot analysis. The RACE was carried out and the gene of 1 597 bp containing polyA in 3'end was obtained, which has an entire open reading frame encoding 437 amino acids. Homology analysis showed that this was a gene encoding human FGG. RT-PCR analysis of FGG showed that the amplification of cancerous tissues, especially in metastasis of HCC, was raised as compared to that of adjacent non-cancerous tissues.
Overexpression of FGG was discovered in SMMC-7721 and HepG2 cells. The up-regulation of FGG may be associated with the pathogenesis of HCC.
基因的异常表达与肝细胞癌（HCC）的发生发展相关；然而，由于目前已知的遗传信息不足，其详细机制尚不清楚。本研究旨在探索人肝细胞癌中差异表达的纤维蛋白原γ多肽（FGG）基因的克隆与鉴定。
采用抑制性消减杂交技术获得HCC的消减cDNA产物，然后通过T/A法进行克隆。通过DNA测序分析、Northern印迹分析、cDNA末端快速扩增（RACE）和逆转录聚合酶链反应（RT-PCR）鉴定该基因在HCC中的差异表达。
首先，从消减cDNA克隆中筛选出一个787个核苷酸的cDNA片段，Northern印迹分析进一步发现，该cDNA片段在SMMC-7721和HepG2人肝癌细胞株中的表达明显高于正常肝细胞。进行RACE，获得了一个3'末端含polyA的1597bp基因，其具有一个完整的开放阅读框，编码437个氨基酸。同源性分析表明，这是一个编码人FGG的基因。FGG的RT-PCR分析显示，与相邻的非癌组织相比，癌组织尤其是HCC转移灶中的扩增增加。
在SMMC-7721和HepG2细胞中发现FGG过表达。FGG的上调可能与HCC的发病机制有关。
