CHARACTERIZATION OF GONAD DEVELOPMENT IN GROUPER WITH GONAD SPECIFIC MARKERS - PIWIL2 AND VASA

Tin-Han Chien*, Chih-Chan Wu, and Tzong-Yueh Chen
Department of Biotechnology and Bioindustry Sciences, Institute of Biotechnology, Translational Center for Marine Biotechnology, Agriculture Biotechnology Research Center, National Cheng Kung University, Tainan 70101, Taiwan
E-mail: L68041060@mail.ncku.edu.tw

Groupers are famous for being a remunerative species of aquaculture in Asia. One of the bottlenecks in giant grouper breeding is their long-term sex maturation which takes as many as 7 to 10 years. The groupers of genus Epinephelus is a protogynous teleost that they only perform sex transformation until a specific body size is reached. To elucidate the gonad formation and sex development process, gonad specific expressed gene, Piwil-2 and Vasa, are cloned for monitoring the germ cells.

Piwil-2 and Vasa are cloned from Epinephelus lanceolatus. Piwil-2, containing conserved PAZ and PIWI domain, is involved in the piRNA pathway related to the germ cell survival and differentiation. Piwil-2 while Vasa is an RNA binding protein with an RNA-dependent helicase responsible for germ cell development. Both the genes are specifically expressed in gonad tissue while other somatic tissues only show low levels of Piwil-2 and Vasa. Anti-Piwil-2 and anti-Vasa antibody is produced in-house for protein level detection. Grouper embryos from 0 to30 days post fertilization are collected for primordial germ cells detection with Piwil-2 and Vasa antibody. Primordial germ cells locate to the gonadal ridge around 3 dpf. It is shown that the molecular markers, Piwil-2 and Vasa, are potential tools for gonad development research.