Project description:We assess gene expression patterns upon 17beta-estradiol (E2) exposure to Japanese medaka (Oryzias latipes) in order to appere the E2 effects using DNA microarray analysis. Larval medaka were exposed to 0, 3, 30 and 100 ng/L of E2 and concentration-dependent changes in gene expressions were examined using Agilent medaka DNA microarrays. At 7 day, fish were sacrificed and mRNA was extracted for gene expression analysis. In an effort to link gene expression changes to effects on higher levels of biological organization, sex characteristics, gonadal histology, GSI, and egg production and fertility were examined. In microarray experiments, the correlation factors between the controls were from 0.91 to 1.00 among control samples. We observed highly induced O. latipes Gene Indices (OLGI) related to egg-yolk protein such as vitellogenin and L-SF precursor etc., which were significantly affected in a concentration-dependent manner by E2 exposure. To clarify the function of expressed genes by E2 treatments, we selected statistically expressed genes from the microarray experiments. We found 190 genes and 72 genes which were statistically expressed in E2 treatment as induced and repressed genes, respectively. In the induced gene list, there were characteristic induced-genes in the categories of lipid metabolism, stress (oxidative stress, DNA and protein damage), and apoptosis with MAPK pathway. On the other hands, there were characteristic repressed genes in the categories of heat shock protein. Our result may suggest that gene expressions in yolk medaka is able to be used for detection of E2 effect by DNA microarray analysis. Larval medaka were exposed to 0, 3, 30 and 100 ng/L of E2 and concentration and time-dependent changes in gene expressions were examined using Agilent medaka DNA microarrays. At 7 day, three independent samples (one sample contained thirty whole medakas) were sacrificed and mRNA was extracted for gene expression analysis.
Project description:We assess gene expression patterns upon 17beta-estradiol (E2) exposure to Japanese medaka (Oryzias latipes) in order to appere the E2 effects using DNA microarray analysis. Larval medaka were exposed to 0, 3, 30 and 100 ng/L of E2 and concentration-dependent changes in gene expressions were examined using Agilent medaka DNA microarrays. At 7 day, fish were sacrificed and mRNA was extracted for gene expression analysis. In an effort to link gene expression changes to effects on higher levels of biological organization, sex characteristics, gonadal histology, GSI, and egg production and fertility were examined. In microarray experiments, the correlation factors between the controls were from 0.91 to 1.00 among control samples. We observed highly induced O. latipes Gene Indices (OLGI) related to egg-yolk protein such as vitellogenin and L-SF precursor etc., which were significantly affected in a concentration-dependent manner by E2 exposure. To clarify the function of expressed genes by E2 treatments, we selected statistically expressed genes from the microarray experiments. We found 190 genes and 72 genes which were statistically expressed in E2 treatment as induced and repressed genes, respectively. In the induced gene list, there were characteristic induced-genes in the categories of lipid metabolism, stress (oxidative stress, DNA and protein damage), and apoptosis with MAPK pathway. On the other hands, there were characteristic repressed genes in the categories of heat shock protein. Our result may suggest that gene expressions in yolk medaka is able to be used for detection of E2 effect by DNA microarray analysis.
Project description:The anabolic androgen 17M-NM-2-trenbolone (TB) can cause masculinization and reduce fecundity of fish. However, the underlying mechanisms of various biological pathways including metabolism, biosynthesis etc. are largely unknown. Here, we evaluated the effects of TB using the medaka DNA microarray representing 36,398 genes. Larval medaka, Oryzias latipes, (within 24 hrs posthatch) were exposed to TB at various concentrations (2, 6, 20, 60, 100, 200 ng/L) for up to 7 days. Dose-response relationships in gene expression levels of the categorized genes were analyzed using the cumulative chisquared method. Microarray analyses of the TB-exposed larvae showed that 117 and 32 genes were determined as up and down-regulated genes, respectively. The most significant GO term for biological process identified within this gene list was lipid metabolic process, which contained 26 genes in up-regulated genes. In this category, M-bM-^@M-^\cholesterol biosynthetic processM-bM-^@M-^] was highlighted as an important subcategory with 15 genes, including hydroxymethylglutaryl-CoA synthase cytoplasmic, squalene monooxygenase, lanosterol synthase etc. RT-PCR measurements in these genes were consistent with the microarray results in the direction and magnitude of these changes in gene expression. On the other hands, in the category of M-bM-^@M-^\sexual differentiation and developmentM-bM-^@M-^], genes related to hypothalamic-pituitary-gonadal (HPG) axis were not affected by TB treatment except for one gene encoded to cytochrome P450 19A1. Genes related to oogenesis, such as choriogenins and vitellogenins were weakly down regulated at 2-200 ng/L of TB. Our findings demonstrate that genes encoding cholesterol synthesis pathway via the mevalonate pathway were controlled by TB in larval medaka. TB concentrations used were 0 (control), 2, 6, 20, 60, 100 and 200 ng/L for 7 days of exposure. Each TB treatment had 90 larval medaka for each chamber. At day 7 of the exposures, triplicate samples (30 larvae/sample) from each chamber respectively were collected, flash-frozen in liquid nitrogen, and stored in liquid nitrogen until RNA extraction.