Germline Specific Expression of a vasa Homologue Gene in the Viviparous Fish Black Rockfish (Sebastes schlegelii) and Functional Analysis of the vasa 3 ' Untranslated Region

Li Zhou; Xueying Wang; Shuran Du; Yanfeng Wang; Haixia Zhao; Tengfei Du; Jiachen Yu; Lele Wu; Zongcheng Song; Qinghua Liu; Jun Li

doi:10.3389/fcell.2020.575788

Germline Specific Expression of a vasa Homologue Gene in the Viviparous Fish Black Rockfish (Sebastes schlegelii) and Functional Analysis of the vasa 3 ' Untranslated Region

Front Cell Dev Biol. 2020 Oct 28:8:575788. doi: 10.3389/fcell.2020.575788. eCollection 2020.

Authors

Li Zhou^{1

2

3}, Xueying Wang^{1

2}, Shuran Du^{1

2}, Yanfeng Wang^{1

2}, Haixia Zhao^{1

2

3}, Tengfei Du^{1

2

3}, Jiachen Yu^{1

2

3}, Lele Wu^{1

2

3}, Zongcheng Song⁴, Qinghua Liu^{1

2}, Jun Li^{1

2}

Affiliations

¹ The Key Laboratory of Experimental Marine Biology, Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China.
² Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.
³ University of Chinese Academy of Sciences, Beijing, China.
⁴ Weihai Shenghang Aquatic Product Science and Technology Co., Ltd., Weihai, China.

Abstract

Germ cells play a key role in gonad development. As precursors, primordial germ cells (PGCs) are particularly important for germline formation. However, the origination and migration patterns of PGCs are poorly studied in marine fish, especially for viviparous economic species. The vasa gene has been widely used as a germ cell marker to identify a germline because vasa RNA is a component of germ plasm. In this study, we described the expression pattern of black rockfish (Sebastes schlegelii) vasa (Ssvas) in gonadal formation and development by in situ hybridization. The results showed that Ssvas failed in localization at the cleavage furrows until the late gastrula stage, when PGCs appeared and migrated to the genital ridge and formed elongated gonadal primordia at 10 days after birth. This study firstly revealed the PGCs origination and migration characteristics in viviparous marine fish. Furthermore, we microinjected chimeric mRNA containing EGFP and the 3'untranslated region (3'UTR) of Ssvas into zebrafish (Danio rerio) and marine medaka (Oryzias melastigma) fertilized eggs for tracing PGCs. We found that, although Sebastes schlegelii lacked early localization, similar to red seabream (Pagrus major) and marine medaka, only the 3'UTR of Ssvas vasa 3'UTR of black rockfish was able to label both zebrafish and marine medaka PGCs. In comparison with other three Euteleostei species, besides some basal motifs, black rockfish had three specific motifs of M10, M12, and M19 just presented in zebrafish, which might play an important role in labeling zebrafish PGCs. These results will promote germ cell manipulation technology development and facilitate artificial reproduction regulation in aquaculture.

Keywords: 3cpsdummy′UTR; Sebastes schlegelii; development; germ cell; gonad; localization; vasa.