Tài liệu Báo cáo khoa học: Dmrt1 genes at the crossroads: a widespread and central class of sexual

MINIREVIEW

Dmrt1 genes at the crossroads: a widespread and central

class of sexual development factors in fish

Amaury Herpin and Manfred Schartl

Physiological Chemistry I, University of Wuerzburg, Germany

Introduction

The phenomenon of two different sexes and conse￾quently the necessity to make a developmental decision

for an embryo to become male or female (the so-called

sex-determination process), and the further differentia￾tion of the whole organism into two distinct phenotypes,

are common throughout the animal, plant and fungi

kingdoms. Nevertheless, with respect to animals at least,

decades of elegant genetic studies have led to the global

picture that the gene-regulatory cascades triggering

sexual differentiation from Caenorhabditis elegans and

Drosophila to mammals bear little resemblance to each

other. Hence, although developmental cascades are

generally headed by highly conserved universal master

regulators that determine the developmental fate of

a cell lineage to a given tissue or organ during embryo￾genesis, all the evidence suggests that sex determination

might disobey the conventional rules of evolutionary

conservation. The common picture emerging here is that

the genes at the top of the cascade are not conserved,

whereas the downstream genes have homologues in a

much broader spectrum of species [1,2]. For example,

SRY, the male sex-determining gene of mammals, has

not been detected outside the eutherians (placental

mammals). Conversely, known downstream effectors

involved in gonadogenesis or gonadal differentiation

like, for example, Wt1, Sox-9, Bmps and Amh (see [3]

for a review) are present in all vertebrates including fish

[4] and for most of them even in protostomes.

Keywords

Dmrt1bY; Evolution; Gonad; Ovary; Sex

determination; Sex differentiation; Steroid

hormones; Teleost; Testis; transcriptional

regulation

Correspondence

A. Herpin, University of Wuerzburg,

Physiological Chemistry, Am Hubland,

D-97074 Wuerzburg, Germany

Fax: +49 931 888 4150

Tel: +49 (0)931 888 4153

E-mail: [email protected]￾wuerzburg.de

(Received 5 August 2010, revised 8

December 2010, accepted 25 January 2011)

doi:10.1111/j.1742-4658.2011.08030.x

A plethora of corroborative genetic studies led to the view that, across the

animal kingdom, the gene-regulatory cascades triggering sexual develop￾ment bear little resemblance to each other. As a result, the common emerg￾ing picture is that the genes at the top of the cascade are not conserved,

whereas the downstream genes have homologues in a much broader spec￾trum of species. Among these downstream effectors, a gene family involved

in sex differentiation in organisms as phylogenetically divergent as corals,

Caenorhabditis elegans, Drosophila, frogs, fish, birds and mammals is the

dmrt gene family. Despite the attention that Dmrt1 factors have received,

to date it has not been elucidated how Dmrt1s mediate their activities and

putative downstream targets have yet to be characterized. However, a

remarkable amount of descriptive expression data has been gathered in a

large variety of fish, particularly with respect to early gonadal differentia￾tion and sex change. This minireview aims at distilling the current knowl￾edge of fish dmrt1s, in terms of expression and regulation. It is shown how

gonadal identities correlate with dimorphic dmrt1 expression in gonochoris￾tic and hermaphroditic fish species. It is also described how sex steroid hor￾mones affect gonadal identity and dmrt1 expression. Emphasis is also given

to recent findings dealing with transcriptional, post-transcriptional, post￾translational and functional regulations of the dmrt1a ⁄ dmrt1bY gene pair

in medaka.

1010 FEBS Journal 278 (2011) 1010–1019 ª 2011 The Authors Journal compilation ª 2011 FEBS