Gene expression patterns - A tool for bioanalysis

Gene expression patterns are efficient tools to elucidate responses to hormones as well as endocrine disruptors at the molecular level. Male zebrafish ( Danio rerio ) were exposed to 17β-estradiol (E2). Transcriptome analysis was first carried out by quantitative polymerase chain reaction (PCR) of the gene coding for vitellogenin (vtg1) in relation to the housekeeping gene ef1α. A significant increase in the expression of vtg1 was found at concentrations >100 ng L^-1 E2. Then DNA microarray experiments were performed to examine the expression levels of the zebrafish genome. A total of 210 sequences were regulated in male zebrafish exposed to 500 ng L ^-1 E2. They include genes involved in the estrogen pathway, such as the gene coding for the estrogen receptor, and in embryonic development, such as homeo box genes. A complete list of up- and down-regulated genes and sequences is provided in this article.