title: Expression analysis of sox3 during testicular development, recrudescence, and after hCG induction in catfish, Clarias batrachus.
abstract: In teleosts, the expression of steroidogenic enzymes and related transcription factor genes occurs in a stage- and tissue-specific manner causing sexual development. The role of sox3, an evolutionary ancestor of SRY, has not been studied in detail. Therefore, the full-length cDNA of sox3 (1,197 kb) was cloned from catfish testis, and mRNA expression was analyzed during gonadal development, during the seasonal reproductive cycle, and after human chorionic gonadotropin (hCG) induction. Tissue distribution analysis showed that sox3 expression was higher in testis, ovary, and brain compared to other tissues analyzed. Developing and mature testis showed higher sox3 expression than ovary of corresponding stages, and more sox3 transcripts were found during the spawning phase of the seasonal reproductive cycle. Expression of sox3 was upregulated by hCG after in vivo and in vitro induction, suggesting that gonadotropins might stimulate it. In situ hybridization and immunohistochemistry showed the presence of sox3 mRNA and protein in somatic and interstitial cell layers of the testis. Sox3 could also be found in the zona radiata of developing and mature oocytes. Exposure of methyltestosterone (1 µg/l) and ethinylestradiol (1 µg/l) for 21 days during testicular development showed lower sox3 expression levels in the testis and brain, indicating a certain feedback intervention. These results suggest a possible role for Sox3 in the regulation of testicular development and function.
authors.affiliation: Laboratory of Molecular Endocrinology and Reproductive Biology, Department of Animal Biology, School of Life Sciences, Centre for Advanced Studies, University of Hyderabad, Hyderabad, India.
authors.forename: Anbazhagan
authors.initials: A
authors.lastname: Rajakumar
authors.forename: Balasubramanian
authors.initials: B
authors.lastname: Senthilkumaran
mesh_terms: D000818:Animals; D015153:Blotting, Western; D001921:Brain / Q000187:drug effects / Q000378:metabolism; D002397:Catfishes / Q000235:genetics* / Q000254:growth & development*; D006063:Chorionic Gonadotropin / Q000494:pharmacology*; D003001:Cloning, Molecular; D004997:Ethinyl Estradiol / Q000494:pharmacology; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects*; D006801:Humans; D008297:Male; D008777:Methyltestosterone / Q000494:pharmacology; D008969:Molecular Sequence Data; D009928:Organ Specificity / Q000187:drug effects / Q000235:genetics; D010802:Phylogeny; D021381:Protein Transport / Q000187:drug effects; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D055748:SOXB1 Transcription Factors / Q000235:genetics* / Q000378:metabolism; D012621:Seasons; D017422:Sequence Analysis, DNA; D013737:Testis / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism*
chemical_list: D006063:Chorionic Gonadotropin; D012333:RNA, Messenger; D055748:SOXB1 Transcription Factors; D004997:Ethinyl Estradiol; D008777:Methyltestosterone