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This Article Full Text Full Text (PDF) All Versions of this Article: 68/5/1545    most recent biolreprod.102.010843v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Yoshiura, Y. Articles by Nagahama, Y. Search for Related Content PubMed PubMed Citation Articles by Yoshiura, Y. Articles by Nagahama, Y. Agricola Articles by Yoshiura, Y. Articles by Nagahama, Y.

Synergistic Expression of Ad4BP/SF-1 and Cytochrome P-450 Aromatase (Ovarian Type) in the Ovary of Nile Tilapia, Oreochromis niloticus, During Vitellogenesis Suggests Transcriptional Interaction¹

Laboratory of Reproductive Biology,³ National Institute for Basic Biology, Okazaki 444-8585, Japan Immunology Section,⁴ Inland Station, National Research Institute of Aquaculture, Tamaki, Mie 519-0423, Japan Department of Biochemistry,⁵ Faculty of Pharmaceutical Sciences, Hoshi University, Shinagawa-Ku, Tokyo 142-0063, Japan Graduate School of Bioagricultural Sciences,⁶ Nagoya University, Nagoya 464-8601, Japan CREST,⁷ Japan Science and Technology Corporation, Kawaguchi, Saitama 332-0012, Japan

Involvement of Ad4BP/SF-1 in the ovarian cytochrome P-450 aromatase (oP450_arom) gene expression was investigated using ovarian follicles of the Nile tilapia, possessing an average 14-day spawning cycle. The promoter region (5' flanking region) of oP450_arom gene cloned from tilapia contains two Ad4 binding sites. Subsequently, a cDNA encoding Ad4BP/SF-1 was cloned from the ovarian follicles. It is expressed in gonadal tissues, brain, and kidney. Oligonucleotide probes containing putative orphan nuclear receptor binding motifs (derived from promoter region of the aromatase gene) formed complexes with in vitro-translated Ad4BP/SF-1 and nuclear extracts of tilapia ovarian (midvitellogenic) follicles, indicating that Ad4BP/SF-1 is one of the transcriptional regulators for aromatase gene expression. Northern blot analysis revealed that the expression of both oP450_arom and Ad4BP/SF-1 increased in parallel with ovarian growth from Day 0 to Day 5 after spawning and declined sharply from Day 8 to Day 11. On the day of spawning (Day 14), the expression of both correlates became undetectable. In vitro incubation of post vitellogenic full-grown immature follicles (corresponding to Day 11 after spawning) with hCG purged both oP450_arom and Ad4BP/SF-1 messenger RNA transcripts at 18 h. Conversely, in vitro incubation of late vitellogenic follicles (corresponding to Day 8 after spawning) with hCG retained Ad4BP/SF-1 messenger RNA transcripts more or less steadily and up-regulated oP450_arom. Ad4BP/SF-1 probably acts as a transcriptional modulator to implement the paradoxical actions of gonadotropins on oP450_arom gene.

¹ Supported in part by Grants-in-Aid for Research for the Future (JSPS-RFTF 96L100401) and Priority Areas (07283101) from the Japan Society for the Promotion of Science; for Scientific Research from the Ministry of Education, Science, Sports, and Culture, Japan; Bio-Design Program from the Ministry of Agriculture, Forestry, and Fisheries, Japan; and CREST of JST (Japan Science and Technology).

² Correspondence: Yoshitaka Nagahama, National Institute for Basic Biology, Okazaki 444-8585, Japan. FAX: 81 564 55 7556; nagahama{at}nibb.ac.jp