Molecular characterization and expression profiling of 3 beta-hydroxysteroid dehydrogenase and hydroxysteroid 17-beta dehydrogenase in response to HCG stimulation in striped murrel, Channa striata (Bloch, 1793)

Striped murrel (Channa striata) is highly valued in the Indian subcontinent and Southeast Asia for its nutritional and medicinal benefits. However, the limited availability of high-quality seeds of murrel and the asynchronous maturation of brooders, particularly during peak spawning seasons creates problems in aquaculture. Beta-hydroxysteroid dehydrogenases (β-HSDs) are steroidogenic enzymes involved in the biosynthesis of active steroids in gametogenesis and steroidogenesis. This study aimed to clone and characterize the full-length cDNA sequences of two crucial enzymes, 3-beta hydroxysteroid dehydrogenase (Hsd3β) and 17-beta hydroxysteroid dehydrogenase (Hsd17β). It resulted in full-length cDNA sequences for Hsd3β and Hsd17β with 1101 bp and 771 bp length, respectively, encoding 366 and 256 amino acids. Signal peptide analysis indicated that both proteins are secretory, and hydropathy profiles suggested their hydrophilic nature. Notably, Rossmann-fold NAD(P)(+)-binding domains characteristic of Short-chain dehydrogenases/reductases (SDR) family genes were identified in Hsd3β (between 9-355 aa) and in Hsd17β (between 10-254 aa). Gene expression analyses were performed in testes and ovaries using qPCR at three key stages: preparatory, mature, and 16 h post human chorionic gonadotropin (hCG) injection (16 hpi). Results demonstrated a significant 2-fold upregulation of Hsd17β in mature and 16 hpi testes, while Hsd3β showed a significant 10-fold upregulation in mature testes compared to premature and 16 hpi stages. Ovarian expression of Hsd3β and Hsd17β showed minimal expression upon hCG injection (P < 0.05). These findings contribute to our understanding of Beta-hydroxysteroid dehydrogenases (β-HSDs), providing insights into regulating sex steroid hormone synthesis during the gonadal development of striped murrel.