Department of Forestry and Natural Resources, Purdue University, West Lafayette, Ind., USA.
Sex Dev. 2013;7(6):308-15. doi: 10.1159/000354280. Epub 2013 Aug 24.
Little is known regarding molecular mechanisms involved in sex determination and differentiation in sturgeon species. We addressed this knowledge gap by using next generation pyrosequencing technology to provide transcript libraries and species-specific sequences for mature gonads of shovelnose sturgeon, Scaphirhynchus platorynchus. We then mined these libraries to identify gender-specific transcripts and quantified relative transcript abundance using quantitative real-time polymerase chain reaction (qPCR). We detected a limited number of genes known to play a role in sex differentiation in other species. The sequence for dmrt1 was found only in the testes library. The abundance of dmrt1 differed slightly between the sexes, but the melt curve suggests that there may be different isoforms of dmrt1 in ovaries and testes of shovelnose sturgeon. The transcription factor foxl2 was 5.3-fold greater in ovaries than in testes. Two antagonists to the Wnt cascade, dickkopf-1 (dkk1) and dapper-1 (dact1), were found only in the ovary library. Results from qPCR indicated that dkk1 and dact1 were upregulated 1,819.1- and 207.5-fold, respectively, in ovaries compared with testes. These results suggest that antagonists to the Wnt cascade may play significant roles in sex differentiation and gonadal development in sturgeon and could serve as sex markers in this group of ancient fish.
关于鲟鱼物种性别决定和分化涉及的分子机制知之甚少。我们使用下一代焦磷酸测序技术提供成熟性腺的转录文库和鲟鱼物种特异性序列来解决这一知识空白，Scaphirhynchus platorynchus。然后，我们从这些文库中挖掘出性别特异性转录本，并使用定量实时聚合酶链反应（qPCR）定量相对转录丰度。我们检测到了一些在其他物种中已知在性别分化中起作用的基因。dmrt1 的序列仅在睾丸文库中发现。dmrt1 的丰度在性别之间略有差异，但熔解曲线表明鲟鱼卵巢和睾丸中可能存在不同的 dmrt1 同工型。转录因子 foxl2 在卵巢中的丰度比在睾丸中高 5.3 倍。Wnt 级联的两种拮抗剂 dickkopf-1（dkk1）和 dapper-1（dact1）仅在卵巢文库中发现。qPCR 结果表明，与睾丸相比，dkk1 和 dact1 在卵巢中分别上调了 1819.1 倍和 207.5 倍。这些结果表明，Wnt 级联的拮抗剂可能在鲟鱼的性别分化和性腺发育中起重要作用，并可作为该组古老鱼类的性别标记。
