Expression of Dmrt1 protein in developing and in sex-reversed gonads of amphibians

Abstract

Many genes are known to be involved in gonadal differentiation in vertebrates. Dmrt1, a gene that encodes a transcription factor with a DM-domain, is considered to be one of the essential genes controlling testicular differentiation in mammals, birds, reptiles, amphibians and fish. However, it still remains unknown which testicular cells of animals other than mice and chicks express Dmrt1 protein. For an explanation of its role(s) in testicular differentiation in vertebrates, the expression of the Dmrt1 protein needs to be studied. For this purpose, we conducted an immunohistochemical study of this protein in an amphibian by using an antibody specific for Dmrt1. No positive signal was found in the indifferent gonad of tadpoles of Rana rugosa at early stages. However, in the testis of tadpoles at later stages (XV–XXV) and in frogs one month after metamorphosis, this protein was expressed in interstitial cells and Sertoli cells. In the testis of adult frogs, germ cells also expressed Dmrt1 protein. RT-PCR analysis revealed that the gene for this protein was not transcribed at any time during ovarian development, but was expressed in the female to male sex-reversed gonad. This was true when immunohistological studies were performed. In addition, Southern blot analysis showed Dmrt1 to be an autosomal gene. Taken together, our findings indicate that Dmrt1 protein is expressed by interstitial cells, Seroli cells and germ cells in the testis of R. rugosa. Dmrt1 may thus be very involved in the testicular differentiation of amphibians.

High-density linkage mapping aided by transcriptomics documents ZW sex determination system in the Chinese mitten crab Eriocheir sinensis

“…In E. sinensis, however, Dmrt1 is on a putative autosome, as in humans (Raymond et al, 1999a) and amphibian Rana rugosa (Aoyama et al, 2003), whereas in chicken and birds, it is Z-linked necessary for testis development (Smith et al, 1999(Smith et al, , 2003Raymond et al, 1999b). Moreover, in contrast to the organisms just mentioned, the expression of this gene in E. sinensis begins at J1, whereas gender is already determined at the earlier M (Lee et al, 1994).…”

Differential and spermatogenic cell-specific expression of DMRT1 during sex reversal in protogynous hermaphroditic groupers

“…Although the expression of DMRT1 in female gonads were reported in various species including reptiles, fishes, birds and mammals (Aoyama et al, 2003;De Grandi et al, 2000;Kettlewell et al, 2000;Marchand et al, 2000;Raymond et al, 1999), knockout analysis in mice demonstrated that DMRT1 is required for mammalian testis differentiation, and not required for the ovary development . Thanks to the hermaphroditic gonad, the grouper DMRT1 was revealed to be expressed only in the spermatogenic cells, whereas no DMRT1 protein was observed in ovarian tissue and oocytes (Fig.…”

“…Especially the finding of DMY, a recent duplicate of DMRT1 in teleost Japanese medaka, was identified as sex determination gene for testis development (Matsuda et al, 2002;Zhang, 2004), indicating that DMRT1 may have important roles in testis determination in teleosts. However, some inconsistent DMRT1 expression patterns have been reported from different species (Aoyama et al, 2003;Gao et al, 2005;Guo et al, 2005;Ohmuro-Matsuyama et al, 2003;Pask et al, 2003). In this study, we selected the interest- Fig.…”

De novotranscriptome sequencing to identify the sex-determination genes inHyriopsis schlegelii

“…Many sex-determination genes, including Sry (sex-determination region of chromosome Y), 1) Sox9 (SRY box-containing gene 9), 2) Dmrt1 (Doublesex and mab3-related transcription factor 1) and Dmrt2 (Doublesex and mab3-related transcription factor 2), 3) Foxl2 (forkhead box L2), 4) Rspo1 (R-spondin1), and β-catenin, 5) have been implicated in sexual determination. Dmrt genes have been identified in species such as mammals, 6) birds, 7) amphibians, 8) and teleosts. 9) However, Sry genes have not been identified in non-mammalian vertebrates.…”