Isolation and Characterization of Testis-Specific DMRT1 in the Tropical Abalone (Haliotis asinina)

The Doublesex Male abnormal-3 Related Transcription factor-1 (DMRT1) gene encodes a protein containing the DNA-binding motif called the DM domain, involved in the sexual development of various species. To gain insight into its implications for gonadal differentiation in the tropical abalone (Haliotis asinina), a DMRT1 homolog was identified and characterized. The full length cDNA of HADMRT1 (1,740 bp with an ORF of 732 bp corresponding to a putative polypeptide of 243 amino acids) and its DM domain-less variant (HADMRT1-like, 1,430 bp with an ORF of 312 bp, 103 amino acids) were successfully isolated and reported for the first time in molluscs. HADMRT1 was specifically expressed in the testes of adult H. asinina (N = 16) but not in whole juveniles (2, 3, 5 months old, N = 6 for each group) and ovaries (N = 16), and pooled hemocytes (from 50 individuals) of adults. Tissue distribution analysis further revealed testis-specific expression of HADMRT1. Semiquantitative RT-PCR illustrated that the relative expression level of HADMRT1 in developed testes (stages II, III, and IV) was significantly greater than that in undeveloped testes (stage I) of abalone broodstock (P < 0.05).