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

TITLE=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

JOURNAL=Frontiers in Cell and Developmental Biology

VOLUME=8

YEAR=2020

URL=https://www.frontiersin.org/journals/cell-and-developmental-biology/articles/10.3389/fcell.2020.575788

DOI=10.3389/fcell.2020.575788

ISSN=2296-634X

ABSTRACT=<p>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 <italic>vasa</italic> gene has been widely used as a germ cell marker to identify a germline because <italic>vasa</italic> RNA is a component of germ plasm. In this study, we described the expression pattern of black rockfish (<italic>Sebastes schlegelii</italic>) <italic>vasa</italic> (<italic>Ssvas</italic>) in gonadal formation and development by <italic>in situ</italic> hybridization. The results showed that <italic>Ssvas</italic> 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 <italic>Ssvas</italic> into zebrafish (<italic>Danio rerio</italic>) and marine medaka (<italic>Oryzias melastigma</italic>) fertilized eggs for tracing PGCs. We found that, although <italic>Sebastes schlegelii</italic> lacked early localization, similar to red seabream (<italic>Pagrus major</italic>) and marine medaka, only the 3′UTR of <italic>Ssvas vasa</italic> 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.</p>