AUTHOR=Wang Wei , Li Bin , Zhou Tingting , Wang Chenggui , Kyei Amankwah Beatrice , Shi Lili , Chan Siuming 

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

JOURNAL=Frontiers in Endocrinology

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/endocrinology/articles/10.3389/fendo.2020.577745

DOI=10.3389/fendo.2020.577745

ISSN=1664-2392

ABSTRACT=<p>In this report, we studied the vitellogenin gene family in the whiteleg shrimp <italic>Litopenaeus vannamei</italic> by transcriptomics, bioinformatics, and molecular biology methods. At least three moderately homologous vitellogenin (Vg) genes (i.e. <italic>LvVg1</italic>, <italic>LvVg2</italic>, and <italic>LvVg3</italic>) 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. <italic>LvVg1</italic> was the most abundant <italic>Vg</italic> expressed in the hepatopancreas and ovary of maturing females. Furthermore, multiple isoforms of <italic>LvVg1</italic> were evolved presumably due to the need for rapid Vg production during the rapid phase of vitellogenesis. <italic>LvVg</italic> transcripts were detected in different larval stages, juveniles, and subadults. During the non-reproductive cycle, <italic>LvVg</italic> expression in the hepatopancreas peaked at the intermolt stages. During the female vitellogenesis cycle, a two-phase expression pattern of <italic>LvVg1</italic> 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 <italic>Vg</italic> 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 <italic>Vg</italic> genes, and it is most likely correlated with the expansion of <italic>Vg</italic>’s function. In conclusion, the evolution of multiple <italic>LvVg1</italic> isoforms and the acquisition of different <italic>Vg</italic> genes (i.e. <italic>LvVg2</italic> and <italic>LvVg3</italic>) may occur universally in most decapods. Full information on the total number of <italic>Vg</italic> genes and precise knowledge on the expression pattern and endocrine regulation of each <italic>Vg</italic> 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.</p>