Interactions between the nuclear matrix and an enhancer of the tryptophan oxygenase gene.
The gene for tryptophan oxygenase (TO) is expressed in adult hepatocytes in a tissue- and differentiation-specific manner. The TO promoter has two glucocorticoid-responsive elements (GREs), and its expression is regulated by glucocorticoid hormone in the liver. We found a novel GRE in close proximity to a scaffold/matrix attachment region (S/MAR) that was located around -8.5kb from the transcriptional start site of the TO gene by electrophoretic mobility shift and chromatin immunoprecipitation (ChIP) assays. A combination of nuclear fractionation and quantitative PCR analysis showed that the S/MAR was tethered to the nuclear matrix in both fetal and adult hepatocytes. ChIP assay showed that, in adult hepatocytes, the S/MAR-GRE and the promoter proximal regions interacted with lamin and heterogeneous nuclear ribonucleoprotein U in a dexamethasone dependent manner, but this was not the case in fetal cells, suggesting that developmental stage-specific expression of the TO gene might rely on the binding of the enhancer (the -8.5kb S/MAR-GRE) and the promoter to the inner nuclear matrix.
Kaneoka
Hidenori
H
Department of Biotechnology, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Japan.
Miyake
Katsuhide
K
Iijima
Shinji
S
D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D047369:Chromatin Immunoprecipitation; D004742:Enhancer Elements, Genetic; D015971:Gene Expression Regulation, Enzymologic; D022781:Hepatocytes / Q000201:enzymology*; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D015530:Nuclear Matrix / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014366:Tryptophan Oxygenase / Q000235:genetics*
D014366:Tryptophan Oxygenase