AUTHOR=Zhang Peng , Yang Yanan , Xu Yuanfeng , Cui Zhaoxia 

TITLE=Analyses of the Dmrt family in a decapod crab, Eriocheir sinensis uncover new facets on the evolution of DM domain genes

JOURNAL=Frontiers in Physiology

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2023.1201846

DOI=10.3389/fphys.2023.1201846

ISSN=1664-042X

ABSTRACT=<p>DM domain genes are a group of transcription factors that are integral to sexual development and its evolution in metazoans. Their functions and regulatory mechanisms are not well understood in Malacostraca (crabs and crayfish) while these sex regulators have been widely identified in the past decade. In this study, the <italic>Dmrt</italic> family was investigated in the decapod crab, <italic>Eriocheir sinensis</italic>. We find that most members of the <italic>EsDmrt</italic> family begin to enrich around the juvenile 1 stage. In reproductive organs, <italic>EsDsx1</italic>, <italic>EsDsx2</italic>, <italic>EsiDMY</italic> and <italic>EsiDmrt1a</italic> highly express in the male-specific androgenic gland (AG), while <italic>EsDmrt-like</italic>, <italic>EsDsx-like</italic>, <italic>EsDmrt11E</italic>, and <italic>EsiDmrt1b</italic> show relatively high expression in testis. Also, we find the highly aberrant expression of <italic>EsiDMY</italic> and <italic>EsiDmrt1a</italic> in the chimeric AG, strongly indicating their function in AG development. Moreover, RNA interference of <italic>EsDsx1</italic>, <italic>EsiDMY</italic>, and <italic>EsiDmrt1a</italic> results in a significant decrease in transcription of the <italic>Insulin-like androgenic hormone</italic> (<italic>IAG</italic>), respectively. Our findings suggest that <italic>Dmrt</italic> genes in <italic>E. sinensis</italic> primarily function in male sexual differentiation, especially in AG development. Besides, this study identifies two unique groups of <italic>Dmrt</italic> genes in Malacostraca: <italic>Dsx</italic> and <italic>iDmrt1</italic>. In Malacostraca <italic>Dsx</italic>, we uncover a cryptic mutation in the eight zinc motif-specific residues, which were firmly believed to be invariant across the <italic>Dmrt</italic> family. This mutation sets the Malacostraca <italic>Dsx</italic> apart from all the other <italic>Dmrt</italic> genes and implies a different way of transcriptional regulation. Genes from the <italic>iDmrt1</italic> group show phylogenetical limitation to the malacostracan species and underwent positive selection, suggesting their highly specialized gene function to this class. Based on these findings, we propose that <italic>Dsx</italic> and <italic>iDmrt1</italic> in Malacostraca have developed unique transcriptional regulation mechanisms to facilitate AG development. We hope that this study would contribute to our understandings of sexual development in Malacostraca and provide new insights into the evolutionary history of the <italic>Dmrt</italic> family.</p>