Germ cells are essential for sexual dimorphism in the medaka gonad

Hiromi Kurokawa, Daisuke Saito, Shuhei Nakamura, Yuko Katoh-Fukui, Kohei Ohta, Takashi Baba, Ken Ichiro Morohashi, Minoru Tanaka

Research output: Contribution to journalArticle

149 Citations (Scopus)

Abstract

To further elucidate the roles of germ cells in the sex differentiation of gonads, we have used the medaka, a teleost fish, to generate mutants that lack germ cells from the onset of gonadogenesis by the morpholino-mediated knockdown of cxcr4. The resulting germ-cell-deficient medaka show female-to-male sex reversal of their secondary sex characteristics, accompanied by increased levels of androgen and reduced levels of estrogen. A failure to maintain granulosa cells or estrogen-producing cells also occurs at early stages of sex differentiation in the cxcr4 morphants, before the initiation of gonadal morphogenesis. In contrast, androgen-producing cells are unaffected in germ-cell-deficient medaka of either sex. In addition, a single tube-like gonad that expresses male-specific genes is formed in these mutants irrespective of the genetic sex. Significantly, each of these mutant phenotypes occurs in a somatic cell-autonomous manner, suggesting that gonadal somatic cells are predisposed toward male development in the absence of germ cells. This highlights the importance of germ cells in the sexual dimorphism of the gonads.

Original languageEnglish
Pages (from-to)16958-16963
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume104
Issue number43
DOIs
Publication statusPublished - Oct 23 2007
Externally publishedYes

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Oryzias
Gonads
Germ Cells
Sex Characteristics
Sex Differentiation
Androgens
Estrogens
Morpholinos
Granulosa Cells
Morphogenesis
Fishes
Phenotype
Genes

All Science Journal Classification (ASJC) codes

  • General

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Germ cells are essential for sexual dimorphism in the medaka gonad. / Kurokawa, Hiromi; Saito, Daisuke; Nakamura, Shuhei; Katoh-Fukui, Yuko; Ohta, Kohei; Baba, Takashi; Morohashi, Ken Ichiro; Tanaka, Minoru.

In: Proceedings of the National Academy of Sciences of the United States of America, Vol. 104, No. 43, 23.10.2007, p. 16958-16963.

Research output: Contribution to journalArticle

Kurokawa, Hiromi ; Saito, Daisuke ; Nakamura, Shuhei ; Katoh-Fukui, Yuko ; Ohta, Kohei ; Baba, Takashi ; Morohashi, Ken Ichiro ; Tanaka, Minoru. / Germ cells are essential for sexual dimorphism in the medaka gonad. In: Proceedings of the National Academy of Sciences of the United States of America. 2007 ; Vol. 104, No. 43. pp. 16958-16963.
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