1. DNA methylation status of cyp17-II gene correlated with its expression pattern and reproductive endocrinology during ovarian development stages of Japanese flounder (Paralichthys olivaceus).
- Author
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Ding Y, He F, Wen H, Li J, Ni M, Chi M, Qian K, Bu Y, Zhang D, Si Y, and Zhao J
- Subjects
- Amino Acid Sequence, Animals, Base Sequence, Binding Sites, CpG Islands, Epigenesis, Genetic, Estradiol blood, Female, Fish Proteins metabolism, Flounder growth & development, Flounder metabolism, Gene Expression, Gene Expression Regulation, Developmental, Molecular Sequence Data, Open Reading Frames, Organ Specificity, Ovary growth & development, Reproduction, Steroid 17-alpha-Hydroxylase metabolism, Testosterone blood, DNA Methylation, Fish Proteins genetics, Flounder genetics, Ovary enzymology, Steroid 17-alpha-Hydroxylase genetics
- Abstract
Cytochrome P450c17-II (cyp17-II, 17α-hydroxylase) is responsible for the production of steroid hormones during oocyte maturation in vertebrates. The comparative expression pattern of cyp17-II gene during the gonadal development stages will provide important insights into its function of gonadal development. In addition, epigenetic modification especially DNA methylation plays a vital role in regulation of gene expression. The adult female Japanese flounder at different ovarian development stage (from stages II to V) was obtained in this experiment. The expression of cyp17-II gene in the ovary of Japanese flounder during the gonadal development stages was measured by quantitative PCR. Reproductive traits included gonadosomatic index (GSI), plasma estradiol-17β (E2) and testosterone (T) were also measured. Moreover, whole CpG dinucleotides methylation status of the two CpG rich regions in cyp17-II coding region was detected by bisulfate sequencing. In the ovary, the cyp17-II gene had the lowest mRNA expression at the early ovarian development stage, but then increased afterward. The variation trends of T and E2 level were consistent with the cyp17-II expression pattern in ovary. In contrast, the whole methylation levels of each CpG rich region (exon 4 and 6) in cyp17-II coding region were declined from stages II to IV, then increased at stage V. The methylation levels of whole CpG sites in each CpG rich region were inversely correlated with the values of ovarian cyp17-II gene expression, T and E2 level, and GSI. Based on the present study, we proposed that cyp17-II may regulate the level of steroid hormone, and then stimulate the oocyte growth and maturation. The cyp17-II gene transcriptional activity was possibly affected by the methylation level of CpG rich regions in coding region. These findings will help in the study of the molecular mechanism of fish reproduction and endocrine physiology., (Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.)
- Published
- 2013
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