DNA methylation and histone acetylation of rat methionine adenosyltransferase 1A and 2A genes is tissue-specific

Methionine adenosyltransferase (MAT) catalyzes the biosynthesis of S-adenos ylmethionine (AdoMet). In mammals MAT activity derives From two separate ge nes which display a tissue-specific pattern of expression, While MAT1A is e xpressed only in the adult liver, MAT2A is expressed in non-hepatic tissues , The mechanisms behind the selective expression of these two, genes are no t fully understood. In the present report we have evaluated MAT1A and MAT2A methylation in liver and in other tissues, such as kidney, by methylation- sensitive restriction enzyme digestion of genomic DNA, Our data indicate th at,MAT1A is hypomethylated in liver and hypermethylated in non-expressing t issues. The opposite situation is found for;MAT2A. Additionally, histones a ssociated to MAT1A and MAT2A genes showed enhanced let els of acetylation i n expressing tissues (two-fold for MAT1A and 3.5-fold for MAT2A liver and k idney respectively). These observations support a role for chromatin struct ure and its modification in the tissue-specific expression of both MAT gene s, (C) 2000 Elsevier Science Ltd, All rights reserved.