Characterization of glycine-N-methyltransferase-gene expression in human hepatocellular carcinoma.
Messenger RNA differential display was used to study liver-gene expression in paired tumor and non-tumor tissues from hepatocellular carcinoma (HCC) patients. mRNA differential display and Northern-blot analyses showed that a 0.8-kb cDNA fragment was diminished or absent from the tumorous tissues of 7 HCC patients. The cDNA fragment was sequenced and found to have 98.7% nucleotide sequence homology with human glycine-N-methyltransferase cDNA (GNMT). In addition, there was no detectable level of GNMT expression in 4 human HCC cell lines, SK-Hep1, Hep 3B, HuH-7 and HA22T, examined by Northern-blot assay. A full-length GNMT cDNA clone-9-1-2 was obtained by screening a Taiwanese liver cDNA library. In comparison with the GNMT cDNA sequence reported elsewhere, clone 9-1-2 had 4 nucleotide differences resulting in 1 amino-acid change. Immunohistochemical staining with rabbit anti-recombinant GNMT serum showed that GNMT protein almost completely disappeared in liver-cancer cells, while it was abundant in the non-tumorous liver cells. Down-regulation of GNMT gene expression may be involved in the pathogenesis of liver cancer.
Chen
Y M
YM
Division of Preventative Medicine, Institute of Public Health, School of Medicine, National Yang-Ming University, Taipei, Taiwan, Republic of China. arthur@ym.edu.tw
Shiu
J Y
JY
Tzeng
S J
SJ
Shih
L S
LS
Chen
Y J
YJ
Lui
W Y
WY
Chen
P H
PH
D000595:Amino Acid Sequence; D001483:Base Sequence; D006528:Carcinoma, Hepatocellular / Q000201:enzymology / Q000235:genetics*; D003001:Cloning, Molecular; D015971:Gene Expression Regulation, Enzymologic; D015972:Gene Expression Regulation, Neoplastic; D050938:Glycine N-Methyltransferase; D006801:Humans; D007150:Immunohistochemistry; D008099:Liver / Q000378:metabolism; D008113:Liver Neoplasms / Q000201:enzymology / Q000235:genetics*; D008780:Methyltransferases / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000235:genetics; D012334:RNA, Neoplasm / Q000235:genetics; D014407:Tumor Cells, Cultured
D012333:RNA, Messenger; D012334:RNA, Neoplasm; D008780:Methyltransferases; C494510:GNMT protein, human; D050938:Glycine N-Methyltransferase