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This Article Full Text Full Text (PDF) All Versions of this Article: JME-09-0011v1 42/5/437    most recent Alert me when this article is cited Alert me if a correction is posted Services 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 Raghuveer, K Articles by Senthilkumaran, B Search for Related Content PubMed PubMed Citation Articles by Raghuveer, K Articles by Senthilkumaran, B

Department of Animal Sciences, School of Life Sciences, University of Hyderabad, PO Central University, Gachibowli, Hyderabad 500 046, Andhra Pradesh, India

(Correspondence should be addressed to B Senthilkumaran; Email: bsksl{at}uohyd.ernet.in)

The double sex and mab-3 related (DM) transcription factor 1 (dmrt1) plays an important role in testicular differentiation. Here, we report cloning of multiple dmrt1s, a full-length and two alternative spliced forms from adult catfish (Clarias gariepinus) testis, which encode predicted proteins of 287 (dmrt1a), 253 (dmrt1b) and 233 (dmrt1c) amino acid residues respectively. Interestingly, dmrt1c lacks the majority of the DM domain. Multiple dmrt1s (dmrt1a and dmrt1c) were obtained from Clarias batrachus as well. Tissue distribution (transcript and protein) of catfish dmrt1 revealed exclusive expression in testis. Semi-quantitative RT-PCR revealed the presence of multiple dmrt1s with high levels of dmrt1a in adult testis but not in ovary. Real-time RT-PCR analysis during testicular cycle showed higher levels of dmrt1 transcripts in preparatory and pre-spawning when compared with spawning and post-spawning phases. Immunocytochemical and immunofluorescence localization revealed the presence of catfish Dmrt1 protein in spermatogonia and spermatocytes, which indicates plausible role in spermatogenesis. Histological analysis indicated initiation of gonadal sex differentiation in catfish around 40–50 days after hatching. The potential role for dmrt1 in testicular differentiation is evident from its stage-dependent elevated expression in developing testis. Furthermore, dimorphic expressions of dmrt1s were evident at different stages of gonadal development or recrudescence in catfish. Treatment of methyl testosterone (MT) during early stages of gonadal sex differentiation resulted in adult males. Interestingly, we also obtained MT-treated fishes having ova-testis gonads. Analysis of dmrt1, sox9a, foxl2 and cyp19a1 expression patterns in MT-treated gonads revealed tissue-specific pattern. These results together suggest that multiple dmrt1s are testis-specific markers in catfish.