Investigation of Gene Sequence Divergence, Expression Dynamics, and Endocrine Regulation of the Vitellogenin Gene Family in the Whiteleg Shrimp Litopenaeus vannamei

In this report, we studied the vitellogenin gene family in the whiteleg shrimp by transcriptomics, bioinformatics, and molecular biology methods. At least three moderately homologous vitellogenin (Vg) genes (i.e. , , and ) were identified in the genome. The deduced LvVg proteins consisted of a vitellogenin_N domain, a DUF1943 domain, and a VWD domain typical of most vitellogenins from oviparous animals. was the most abundant expressed in the hepatopancreas and ovary of maturing females. Furthermore, multiple isoforms of were evolved presumably due to the need for rapid Vg production during the rapid phase of vitellogenesis. transcripts were detected in different larval stages, juveniles, and subadults. During the non-reproductive cycle, expression in the hepatopancreas peaked at the intermolt stages. During the female vitellogenesis cycle, a two-phase expression pattern of gene was observed in the hepatopancreas and ovary. Moreover, the eyestalk optic nerve, brain, and thoracic ganglion consisted of factors that differentially regulated the expression of the three genes. In addition to their reproduction-related roles, Vg may also be involved in growth and molt-related processes. Phylogenetic analysis revealed the early expansion and separation of these genes, and it is most likely correlated with the expansion of 's function. In conclusion, the evolution of multiple isoforms and the acquisition of different genes (i.e. and ) may occur universally in most decapods. Full information on the total number of genes and precise knowledge on the expression pattern and endocrine regulation of each during all life cycle stages are crucial for us to understand the roles of this emerging gene family in the control of shrimp reproduction and other non-reproductive processes.