Expression of non-hepatic-type S-adenosylmethionine synthetase isozyme in rat hepatomas induced by 3'-methyl-4-dimethylaminoazobenzene.
It is known that a high incidence of hepatocellular carcinoma in rat liver can be induced by such azo dye carcinogens as 3'-methyl-4-dimethylaminoazobenzene (3'-MeDAB). Mammalian S-adenosylmethionine (AdoMet) synthetase exists as two isozymes, non-hepatic-type and liver-type enzymes, which are the products of two different genes. We have examined the expression of two AdoMet synthetase isozyme proteins and mRNAs in rat hepatomas induced by 3'-Me-DAB. The levels of non-hepatic-type enzyme protein and mRNA are clearly induced by 3'-Me-DAB feeding. On the other hand, the levels of liver-type enzyme protein and mRNA are nearly the same or slightly decreased during hepatocarcinogenesis. These results indicate that the expression of the non-hepatic-type isozyme gene is obviously influenced with the progression of carcinogenesis and that the non-hepatic-type isozyme is useful as a oncodevelopmental marker in the liver.
Horikawa
S
S
Department of Pathological Biochemistry, Tokyo Medical and Dental University, Japan.
Kobayashi
Y
Y
Sugiyama
T
T
Terashima
H
H
Wada
K
K
Tsukada
K
K
Hirokawa S [corrected to Horikawa
S ]
S]
D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western; D007527:Isoenzymes / Q000096:biosynthesis*; D008114:Liver Neoplasms, Experimental / Q000139:chemically induced / Q000201:enzymology*; D008297:Male; D008716:Methionine Adenosyltransferase / Q000096:biosynthesis* / Q000235:genetics; D008749:Methyldimethylaminoazobenzene / Q000494:pharmacology*; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley
D007527:Isoenzymes; D012333:RNA, Messenger; D008749:Methyldimethylaminoazobenzene; D008716:Methionine Adenosyltransferase