Open AccessSexually dimorphic expression of Dmrt1 and γH2 AX in germ stem cells during gonadal development in Xenopus laevis
Author(s) -
Fujitani Kazuko,
Otomo Asako,
Wada Mikako,
Takamatsu Nobuhiko,
Ito Michihiko
Publication year - 2016
Publication title -
febs open bio
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.718
H-Index - 31
ISSN - 2211-5463
DOI - 10.1002/2211-5463.12035
Subject(s) - biology , xenopus , somatic cell , development of the gonads , epigenetics , sexual differentiation , metamorphosis , germ cell , gonad , microbiology and biotechnology , medicine , sox9 , disorders of sex development , endocrinology , andrology , transcription factor , genetics , gene , botany , larva
In many animals, primordial germ cells ( PGC s) migrate into developing gonads. There, they proliferate and differentiate into female and male germ stem cells ( GSC s), oogonia and spermatogonia, respectively. Few studies have focused on the molecular mechanisms underlying the development of GSC sex determination. Here, we investigated the expression of the transcription factor Dmrt1 and a phosphorylated form of the histone variant H2 AX (γH2 AX ) during gonadal development in Xenopus laevis . During early sexual differentiation, Dmrt1 was expressed in the GSC s of the ZW (female) and ZZ (male) gonads as well as somatic cells of the ZZ gonads. Notably, the PGC s and primary GSC s contained large, unstructured nuclei, whereas condensed, rounder nuclei appeared only in primary oogonia during tadpole development. After metamorphosis, Dmrt1 showed its expression in secondary spermatogonia, but not in secondary oogonia. Like Dmrt1, γH2 AX was expressed in the nuclei of primary GSC s in early developing gonads. However, after metamorphosis, γH2 AX expression continued in primary and secondary spermatogonia, but was barely detected in the condensed nuclei of primary oogonia. Taken together, these observations indicate that spermatogonia tend to retain PGC characteristics, compared to oogonia, which undergo substantial changes during gonadal differentiation in X. laevis . Our findings suggest that Dmrt1 and γH2 AX may contribute to the maintenance of stem cell identity by controlling gene expression and epigenetic changes, respectively.