Protein methylation in cellular proliferation and differentiation: Non-histone nuclear methyl acceptor protein(s) during 3'-methyl-4-dimethylaminoazobenzeneinduced hepatocarcinogenesis.
- Author:
Moon Kee PAIK
1
;
Yoo Jeong HAN
;
Jung Hee HONG
;
Jung Sook KIM
;
Kwang Sun SUH
;
Se Jin YOON
Author Information
1. WONKWANG UNIV, SCH MED, DEPT BIOCHEM, IKSAN, SOUTH KOREA.
- Publication Type:Original Article
- Keywords:
protein methyltransferases;
cell division;
cell differentiation;
nuclear proteins;
rat;
dimethylaminoazobenzene;
hepatoma;
carcinogens
- MeSH:
Amino Acids;
Animals;
Arginine;
Carcinogens;
Carcinoma, Hepatocellular;
Cell Differentiation;
Cell Division;
Cell Proliferation*;
Cholangiocarcinoma;
Diet;
Food, Formulated;
Liver;
Methylation*;
Nuclear Proteins;
p-Dimethylaminoazobenzene;
Placental Lactogen;
Protein Methyltransferases;
Protein-Arginine N-Methyltransferases;
Rats;
S-Adenosylmethionine;
Sequence Homology
- From:Experimental & Molecular Medicine
1997;29(1):35-43
- CountryRepublic of Korea
- Language:English
-
Abstract:
An accelerating effect of methyl-deficient diet (MDD) on hepatocarcinogenesis and methylation pattern of nuclear protein(s) by S-adenosylmethionine: protein arginine N-methyltransferase (protein methylase I, PM-I) have been studied with 3'-methyl-4-dimethyl- aminoazobenzene(MeDAB)-treated rats. The MDD+MeDAB-fed group produced typical cancer cells in the liver almost two weeks earlier than the control synthetic diet (CSD)+MeDAB-fed group. Protein methylase I (PM-I) activity in the livers of MDD alone fed rats began to increase at around 2 weeks after MDD-feeding, reaching a peak at 4 weeks and declining thereafter. When nuclei isolated either from normal livers or from cholangiocarcinoma cells were incubated with PM-I preparation from normal liver, 16 and 23-kDa nuclear proteins were the major methylated proteins, regardless of the source of the nuclei. However, when the above mentioned nuclei were incubated with PM-I preparations either from MDD alone fed livers or MDD+ MeDAB-induced cholangiocarcinoma cells, the methylation of 23-kDa protein was not detected. The result suggests that there is a hitherto-unknown PM-I specific to 23 kDa nuclear protein which was lost during methyl deficient diet feeding and hepatocarcinogenesis. The N-terminal 20 amino acids sequence of the 23-kDa protein was found to be (1)Gly-Val-Pro-Leu-(5)X-Arg-Leu-Phe-Asp-(10)His-Ala-Met-Leu-Gln-(15)Ala -His-Arg-Ala-His-(20)Glu, having 94.7% sequence homology with human chorionic somatomammotropin precursor A and B.
