Search for the sex-determining switch in monotremes: Mapping WT1, SF1, LHX1, LHX2, FGF9, WNT4, RSPO1 and GATA4 in platypus

Grafodatskaya, Daria; Rens, Willem; Wallis, Mary; Trifonov, Vladimir A.; O’Brien, Patrícia C. M.; Clarke, Oliver; Graves, Jennifer A. Marshall; Ferguson‐Smith, Malcolm A.

doi:10.1007/s10577-007-1161-y

Cited by 25 publications

(24 citation statements)

References 37 publications

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“…For instance, the unpaired part of X 5 contains the DMRT1 gene that is a candidate for sex determination in birds and for sex reversal in humans; however, it is present in two doses in females and one in males (which is the opposite situation from birds), and therefore is unlikely to play the role of sex-determining switch in platypus (El-Mogharbel et al 2007;Wallis et al 2007). Grafodatskaya et al (2007) demonstrated that GATA4, a gene that interacts with human and mouse male gonad development, lies on the platypus sex chromosomes, but on the Y 1 /X 2 pairing region, and is therefore a poor sexdetermining candidate. Other putative sex-determining genes (genes know to play a role in vertebrate sex determination) lie on autosomes ); thus the hunt for a putative platypus sex-determining switch continues.…”

Section: Platypus Y Chromosomes and Platypus Sex Determinationmentioning

confidence: 99%

Bird-like sex chromosomes of platypus imply recent origin of mammal sex chromosomes

Veyrunes¹,

Waters²,

Miethke³

et al. 2008

Genome Res.

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In therian mammals (placentals and marsupials), sex is determined by an XX female: XY male system, in which a gene (SRY) on the Y affects male determination. There is no equivalent in other amniotes, although some taxa (notably birds and snakes) have differentiated sex chromosomes. Birds have a ZW female: ZZ male system with no homology with mammal sex chromosomes, in which dosage of a Z-borne gene (possibly DMRT1) affects male determination. As the most basal mammal group, the egg-laying monotremes are ideal for determining how the therian XY system evolved. The platypus has an extraordinary sex chromosome complex, in which five X and five Y chromosomes pair in a translocation chain of alternating X and Y chromosomes. We used physical mapping to identify genes on the pairing regions between adjacent X and Y chromosomes. Most significantly, comparative mapping shows that, contrary to earlier reports, there is no homology between the platypus and therian X chromosomes. Orthologs of genes in the conserved region of the human X (including SOX3, the gene from which SRY evolved) all map to platypus chromosome 6, which therefore represents the ancestral autosome from which the therian X and Y pair derived. Rather, the platypus X chromosomes have substantial homology with the bird Z chromosome (including DMRT1) and to segments syntenic with this region in the human genome. Thus, platypus sex chromosomes have strong homology with bird, but not to therian sex chromosomes, implying that the therian X and Y chromosomes (and the SRY gene) evolved from an autosomal pair after the divergence of monotremes only 166 million years ago. Therefore, the therian X and Y are more than 145 million years younger than previously thought.

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Section: Platypus Y Chromosomes and Platypus Sex Determinationmentioning

confidence: 99%

Bird-like sex chromosomes of platypus imply recent origin of mammal sex chromosomes

Veyrunes¹,

Waters²,

Miethke³

et al. 2008

Genome Res.

Self Cite

278

258

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“…DMRT1, the putative sex-determining gene in birds (Smith et al, 2009), is located on platypus chromosome X 5 (Grützner et al, 2004), but it is doubtful that it could be a sex-determining gene in platypus, because it is present in two copies in female and single copy in males, which is opposite to its dosage in chicken (two copies in males). Accordingly, the platypus sex-determining gene remains unknown (Grafodatskaya et al, 2007).…”

Section: Marsupial Sex Chromosomesmentioning

confidence: 99%

The origin and evolution of vertebrate sex chromosomes and dosage compensation

2011

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In mammals, birds, snakes and many lizards and fish, sex is determined genetically (either male XY heterogamy or female ZW heterogamy), whereas in alligators, and in many reptiles and turtles, the temperature at which eggs are incubated determines sex. Evidently, different sex-determining systems (and sex chromosome pairs) have evolved independently in different vertebrate lineages. Homology shared by Xs and Ys (and Zs and Ws) within species demonstrates that differentiated sex chromosomes were once homologous, and that the sex-specific non-recombining Y (or W) was progressively degraded. Consequently, genes are left in single copy in the heterogametic sex, which results in an imbalance of the dosage of genes on the sex chromosomes between the sexes, and also relative to the autosomes. Dosage compensation has evolved in diverse species to compensate for these dose differences, with the stringency of compensation apparently differing greatly between lineages, perhaps reflecting the concentration of genes on the original autosome pair that required dosage compensation. We discuss the organization and evolution of amniote sex chromosomes, and hypothesize that dosage insensitivity might predispose an autosome to evolving function as a sex chromosome.

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“…Interestingly, GATA4 was found to be on the sex chromosomes in the platypus (Ornithorhynchus anatinus) [21]. However, GATA4 is not considered to be a good candidate gene for sex determination in monotremes because it maps to the pairing regions and is present in the same dose in both males and females [21].Although the role of GATA4 in mammalian reproduction has been well demonstrated [22][23][24][25][26][27][28][29], the reproductive functions of GATA4 remain elusive in nonmammalian vertebrates. In the chicken, GATA4 showed no sexual dimorphic expression during sexual differentiation [30,31].…”

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confidence: 99%

“…While Sf1Cre-mediated excision of Gata4 permitted normal expression of most genes associated with embryonic testis development, gonadal loss of Fog2 resulted in an early partial block in the male pathway and sex reversal. Interestingly, GATA4 was found to be on the sex chromosomes in the platypus (Ornithorhynchus anatinus) [21]. However, GATA4 is not considered to be a good candidate gene for sex determination in monotremes because it maps to the pairing regions and is present in the same dose in both males and females [21].…”

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confidence: 99%

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GATA4 is Involved in the Gonadal Development and Maturation of the Teleost Fish Tilapia, <i>Oreochromis niloticus</i>

Chen

Wang

et al. 2012

J. Reprod. Dev.

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Abstract. GATA4, a member of the GATA family, is a well-known transcription factor implicated in the regulation of sex determination and sexual differentiation in mammals. However, little is known about the possible role of GATA4 in fish reproduction. In the present study, a full-length GATA4 cDNA from the tilapia was cloned and characterized. The tilapia GATA4 gene contained an open reading frame (ORF) of 1179 nucleotides encoding a protein of 392 amino acids. Sequence alignment revealed that the tilapia GATA4 protein shared higher homology (ranging from 63.1 to 74.6%) with other vertebrates. RT-PCR analysis indicated that the GATA4 gene is expressed in the ovary, testis, liver, intestine and heart in adult tilapia. In situ hybridization was performed to examine the temporal and spatial expression patterns of GATA4 during tilapia gonadal differentiation and development. In the undifferentiated gonad, GATA4 was expressed in the somatic cells of both sexes. Subsequently, GATA4 expression persisted in the differentiated, juvenile and adult ovary and testis in tilapia. Our data indicate for the first time that GATA4 is not only necessary for the onset of gonadal differentiation, but also important for gonadal development and maturation. Key words: GATA4, Gonadal development, Gonadal maturation, Sexual differentiation, Tilapia GATA4 is a member of the GATA family of zinc finger DNAbinding proteins that recognize the consensus nucleotide sequence WGATAR (called the GATA motif) in the promoter region of target genes in vertebrates [1]. It has been regarded as an important developmental determinant for many organs, such as the heart, liver, lung, stomach, gut, ovary and testis [2,3]. In the mouse, GATA4 is strongly expressed in somatic cells of both the XX and XY genital ridge at embryonic stage 11.5 (E11.5). At E13.5, GATA4 expression becomes sexually dimorphic: in XY gonads, expression is upregulated in Sertoli cells and downregulated in interstitial cells, whereas in XX gonads, expression is downregulated in all cells. GATA4 expression continues in the somatic cells of postnatal testes and is reactivated in adult ovaries with predominant expression in granulosa cells [4][5][6].GATA4 has been shown to regulate the transcription of numerous target genes [7]. To date, proposed target genes in the gonad include the sex-determining genes SRY and SOX9, as well as key steroidogenic factors such as AMH [8, 9], INHA [10], STAR [11, 12], CYP19A1, CYP11A1, CYP17A1, HSD17B1 and HSD3B2 [13]. GATA4 interacts with several proteins, including its cofactors FOG2, SF-1/ NR5A1 and LRH-1/NR5A2 [7]. Interactions between GATA4 and FOG2 are required for sex determination, sexual differentiation and gonadal development in mammals [14][15][16][17][18][19][20]. A recent report suggests that GATA4 is required for testis differentiation, for the expression of Dmrt1 gene and for testis cord morphogenesis in mice [17]. While Sf1Cre-mediated excision of Gata4 permitted normal expression of most genes associated with embryonic testis development...

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Search for the sex-determining switch in monotremes: Mapping WT1, SF1, LHX1, LHX2, FGF9, WNT4, RSPO1 and GATA4 in platypus

Cited by 25 publications

References 37 publications

Bird-like sex chromosomes of platypus imply recent origin of mammal sex chromosomes

Bird-like sex chromosomes of platypus imply recent origin of mammal sex chromosomes

The origin and evolution of vertebrate sex chromosomes and dosage compensation

GATA4 is Involved in the Gonadal Development and Maturation of the Teleost Fish Tilapia, <i>Oreochromis niloticus</i>

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