WD Repeat-containing Protein 73, A Novel Gene Correlated with Gonad Development in Large Yellow Croaker, Larimichthys crocea

The genome of Larimichthys crocea harbors more than 200 putative WD40 proteins. Yet, the function of these WD40 proteins remains unknown. Here a WD40 gene, wd73, was cloned and characterized in L. crocea (named as Lcwdr73). The cDNA is 1706 bp, including a 5′ untranslated region (UTR) of 51 bp, a 3′ UTR of 509 bp, and an open reading frame of 1146 bp encoding 381 amino acid residues. The putative LcWDR73 protein contains three WD40 domain motifs. The tissue expression profiles of both sexes revealed that Lcwdr73 was extremely highly expressed in testis and ovary, moderate in kidney and brain, and low in the other tissues by quantitative polymerase chain reaction analysis. Based on histology, the gonad development of L. crocea was divided into four phases: proliferative stage (Phase I), small developmental stage (Phase II), grand developmental stage (Phase III), and mature stage (Phase IV). With the gonad development, Lcwdr73 mRNA increased and reached a peak in Phase IV, and the expression in testes is significantly higher than that in ovaries, especially from Phase II to Phase IV, indicating that Lcwdr73 may play an important role during gonad development in L. crocea. The resutlts lay a foundation to control precocious puberty of L. crocea.