Sox9 gene expression during ontogeny stages and various tissues of Persian sturgeon, Acipenser persicus (Borodin, 1897)

Sox9 is a protein-coding gene that plays a critical role during organogenesis and regulation of the male gonad development among vertebrates. Knowledge about the expression of Sox9 during larval development can help to complete the lack of the information on its possible function in sturgeon fishes. Due to the importance of the Persian sturgeon as a valuable candidate species for aquaculture and the importance of Sox9 gene in vertebrate evolution, in this study, Sox9 cDNA was characterized and the expression pattern during various ontogeny stages (unfertilized egg to 210 days post hatching - dph) and among ten different tissues (gill, pyloric, spleen, gonad, kidney, intestine, heart, skin, liver, muscle) was analyzed using RT-PCR method. Results indicated that Sox9 mRNA was not detect in unfertilized and fertilized egg. However, first expression was measured at 1 dph then Sox9 mRNAs decreased in a gradual manner during the 1 to 50 dph and declined to minimal level at 210 dph (P<0.05). Also, Sox9 mRNA was present in most tissues with the highest expression in the gill and pyloric, weakly expression in the liver and gonad and no expression in the muscle. Our findings suggest that Sox9 was not applicable in sex determination in early developmental stages and probably it can be implicated in other developmental activities such as chondrogenesis.