Abstract
Arabidopsis mutant lines generated with ethylmethan sulfonate (EMS) have been selected using reporter genes under the regulation of photosynthesis gene RBCS-3B promoter in order to reveal the mechanisms underlying the organ-specific gene expression. It has been found that gene expression suppressed by exogenous promoters but not by endogenous ones is specifically released in rex2 (relaxed expression of transgenes) line.
DNA methylation status has been analyzed with bisulfite to realize the epigenetic regulation involved in the phenomenon that endogenous and exogenous promoters have the common sequences but the different activities. Methylated cytosine has barely been detected in the exogenous promoter, whereas some methylation has been done in the endogenous one. Furthermore, focusing on chromatin structure and modification of histon proteins, difference in the chromatin structure of exogenous and endogenous promoters has been examined. The mutated region has been narrowed within 50 kbp by genetic analysis, and further subjected to nucleotide sequencing.
