Molecular Cloning and Sexually Dimorphic Expression of Two Dmrt Genes in the Giant Freshwater Prawn, Macrobrachium rosenbergii

Abstract

The molecular mechanism of sex determination changed rapidly during evolution among phyla. One exception is the Dmrt (doublesex and mab-3 related transcription factor) family gene, which is widely conserved for its involvement in sex development from invertebrates to humans. In this study, we identified two DM-domain genes in the giant freshwater prawn, Macrobrachium rosenbergii, which we named MroDmrt11E and MroDmrt99B according to their high similarities and phylogenetically close relationships with arthropod Dmrt11E and Dmrt99B genes, respectively. Amino acid alignments and structural prediction uncovered conservation and putative active sites of their DM domains. Realtime PCR analysis exhibits a sexually dimorphic and embryonic development-dependent expression pattern of both genes. The transcription of both MroDmrt11E and MroDmrt99B was prominent in testis, and both mRNAs were localized in spermatogonia and spermatozoa during spermatogenesis. RNAi-targeting MroDmrt99B showed no effect on several male-reproduction related genes while the MroDmrt11E RNAi induced a significant decrease of the transcript of Iag, an important regulatory gene in the male determination mechanism of the prawn. The complicated expression profiles of Dmrt family genes and closely related subfamily members may provide clues of their rapid evolution and multi-functionality. Our study will contribute to understanding mechanistic and evolutionary dynamics of Dmrt family genes in metazoan bisexual development and embryogenesis.