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Jiménez R, Barrionuevo FJ, Burgos M. Natural exceptions to normal gonad development in mammals. Sex Dev 2012; 7:147-62. [PMID: 22626995 DOI: 10.1159/000338768] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Gonads are the only organs with 2 possible developmental pathways, testis or ovary. A consequence of this unique feature is that mutations in genes controlling gonad development give rise not only to gonadal malformation or dysfunction but also to frequent cases of sex reversal, including XY females, XX males and intersexes. Most of our current knowledge on mammalian sex determination, the genetic process by which the gonadal primordia are committed to differentiate as either testes or ovaries, has derived mainly from the study of sex-reversed mice obtained by direct genetic manipulation. However, there are also numerous cases of natural exceptions to normal gonad development which have been described in a variety of mammals, including both domestic and wild species. Here, we review the most relevant cases of: (1) natural, non-induced sex reversal and intersexuality described in laboratory rodents, including Sxr and B6-Y(DOM) mice; (2) sex reversal in domestic animals, including freemartinism in bovids and pigs, XX sex reversal in pigs, goats and dogs, XY sex reversal in the horse, and sex chromosome chimerism and sex reversal in the cat, and (3) sex reversal in wild mammals, including the generalised true hermaphroditism described in talpid moles, XY sex reversal in Akodon, Microtus and Dicrostonyx species, males lacking a Y chromosome and SRY in Ellobius lutescens, the X* chromosome of Myopus schisticolor, and sex chromosome mosaicism and X0 females in Microtus oregoni. These studies are necessary to elucidate particular aspects of mammalian gonad development in some instances and to understand how the genetic mechanisms controlling gonad development have evolved.
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Affiliation(s)
- R Jiménez
- Departamento de Genética e Instituto de Biotecnología, Universidad de Granada, Laboratorio 127 CIBM, Centro de Investigación Biomédica, ES–18100 Armilla, Granada, Spain.
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Lopes AM, Burgoyne PS, Ojarikre A, Bauer J, Sargent CA, Amorim A, Affara NA. Transcriptional changes in response to X chromosome dosage in the mouse: implications for X inactivation and the molecular basis of Turner Syndrome. BMC Genomics 2010; 11:82. [PMID: 20122165 PMCID: PMC2837040 DOI: 10.1186/1471-2164-11-82] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2009] [Accepted: 02/01/2010] [Indexed: 11/12/2022] Open
Abstract
Background X monosomic mice (39,XO) have a remarkably mild phenotype when compared to women with Turner syndrome (45,XO). The generally accepted hypothesis to explain this discrepancy is that the number of genes on the mouse X chromosome which escape X inactivation, and thus are expressed at higher levels in females, is very small. However this hypothesis has never been tested and only a small number of genes have been assayed for their X-inactivation status in the mouse. We performed a global expression analysis in four somatic tissues (brain, liver, kidney and muscle) of adult 40,XX and 39,XO mice using the Illumina Mouse WG-6 v1_1 Expression BeadChip and an extensive validation by quantitative real time PCR, in order to identify which genes are expressed from both X chromosomes. Results We identified several genes on the X chromosome which are overexpressed in XX females, including those previously reported as escaping X inactivation, as well as new candidates. However, the results obtained by microarray and qPCR were not fully concordant, illustrating the difficulty in ascertaining modest fold changes, such as those expected for genes escaping X inactivation. Remarkably, considerable variation was observed between tissues, suggesting that inactivation patterns may be tissue-dependent. Our analysis also exposed several autosomal genes involved in mitochondrial metabolism and in protein translation which are differentially expressed between XX and XO mice, revealing secondary transcriptional changes to the alteration in X chromosome dosage. Conclusions Our results support the prediction that the mouse inactive X chromosome is largely silent, while providing a list of the genes potentially escaping X inactivation in rodents. Although the lower expression of X-linked genes in XO mice may not be relevant in the particular tissues/systems which are affected in human X chromosome monosomy, genes deregulated in XO mice are good candidates for further study in an involvement in Turner Syndrome phenotype.
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Affiliation(s)
- Alexandra M Lopes
- IPATIMUP, Instituto de Patologia e Imunologia Molecular da Universidade do Porto, 4200-465 Porto, Portugal.
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Abstract
The inactive X chromosome differs from the active X in a number of ways; some of these, such as allocyclic replication and altered histone acetylation, are associated with all types of epigenetic silencing, whereas others, such as DNA methylation, are of more restricted use. These features are acquired progressively by the inactive X after onset of initiation. Initiation of X-inactivation is controlled by the X-inactivation center (Xic) and influenced by the X chromosome controlling element (Xce), which causes primary nonrandom X-inactivation. Other examples of nonrandom X-inactivation are also presented in this review. The definition of a major role for Xist, a noncoding RNA, in X-inactivation has enabled investigation of the mechanism leading to establishment of the heterochromatinized X-chromosome and also of the interactions between X-inactivation and imprinting as well as between X-inactivation and developmental processes in the early embryo.
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Affiliation(s)
- E Heard
- Unité de Génétique Moléculaire Murine, URA CNRS 1968, Institut Pasteur, Paris, France.
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4
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Molecular genetics of X-chromosome inactivation. ACTA ACUST UNITED AC 1996. [DOI: 10.1016/s1067-5701(96)80006-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Mortaud S, Donsez-Darcel E, Roubertoux PL, Degrelle H. Murine steroid sulfatase (mSTS): purification, characterization and measurement by ELISA. J Steroid Biochem Mol Biol 1995; 52:91-6. [PMID: 7857878 DOI: 10.1016/0960-0760(94)00143-a] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The murine steroid sulfatase (mSTS) is a microsomal enzyme, important in steroid metabolism. In the mouse, the gene encoding mSTS is pseudoautosomal and thus escapes X-inactivation. We have purified steroid sulfatase approximately 30-fold from mouse liver microsomes and its properties have been investigated. The major steps in the purification procedure included solubilization with Triton X-100, gel filtration chromatography, DEAE-Sephadex chromatography and HPLC gel filtration chromatography. The purified sulfatase showed a relative molecular weight of 128 kDa on HPLC gel filtration, whereas the enzyme migrated as two bands of 60 and 68 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The isoelectric point of steroid sulfatase was estimated to be 6.2 by column chromatofocusing. Polyclonal antibodies to the purified protein were prepared. An Enzyme Linked Immunosorbent Assay (ELISA) was developed using purified monospecific anti-mSTS antibodies labelled with peroxidase. The standard criteria of precision and reproducibility were satisfied. The assay was applicable to routine determination of mSTS samples in research laboratories. Differences in mSTS liver concentrations were used to identify putative alleles for the mSTS gene (Sts). Results in ELISA confirmed the polymorphism previously demonstrated for an enzymatic mSTS activity assay in two inbred mouse strains.
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Affiliation(s)
- S Mortaud
- URA CNRS 1294 Génétique, Neurogénétique et Comportement, U.F.R. Biomédicale des Saints-Pères, Université Paris V-René Descartes, France
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Hurst LD. Embryonic growth and the evolution of the mammalian Y chromosome. II. Suppression of selfish Y-linked growth factors may explain escape from X-inactivation and rapid evolution of Sry. Heredity (Edinb) 1994; 73 ( Pt 3):233-43. [PMID: 7928394 DOI: 10.1038/hdy.1994.128] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The mammalian Y chromosome may be an attractor for selfish growth factors. A suppressor of the selfish growth effects would be expected to spread were it to have an appropriate parent-specific expression rule. A suppressor could act by boosting the resource demands of competing female embryos. This possibility may explain incidences of the escape from X-inactivation and provides a rationale for why these genes typically have Y-linked homologues. Alternatively, a suppressor could act to decrease the resource demands of males with the selfish Y. This possibility is supported by the finding that the size of male, but not female, human infants is negatively correlated to the number of X chromosomes. A protracted arms race between a selfish gene and its suppressor may ensue. Both the variation in copy number of Zfy and the unusually fast sequence evolution of Sry may be explained by such an arms race. As required by the model, human Sry is known to have an X-linked suppressor. Preliminary evidence suggests that, as predicted, rapid sequence evolution of Sry may be correlated with female promiscuity. The case for fast sequence evolution as the product of maternal/foetal conflict is strengthened by consideration of the rapid evolution of placental lactogens in both ruminants and rodents.
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Pravtcheva DD, Wise TL, Ensor NJ, Ruddle FH. Mosaic expression of an Hprt transgene integrated in a region of Y heterochromatin. THE JOURNAL OF EXPERIMENTAL ZOOLOGY 1994; 268:452-68. [PMID: 8176360 DOI: 10.1002/jez.1402680606] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The sensitivity of small transgenes to position effects on their expression suggests that they could serve as indicators of the chromatin properties at their integration site. In particular, they might be expected to provide information on the functional properties of mammalian heterochromatin. We have produced a transgenic line that carries a mouse Hprt minigene on the Y chromosome. In situ hybridization localized the transgene to the heterochromatic portion of the Y. Analysis of transgene expression by isoelectric focusing indicated that the transgene is expressed in a mosaic pattern, and expressing cells have different levels of transgene activity. These findings can be explained as a position effect variegation induced by Y heterochromatin. However, two other transgenes, located at autosomal sites, also showed mosaic activity. If the mosaic transgene expression is attributed to the influence of the chromatin at the insertion site, the Y heterochromatin would appear less potent than some autosomal regions at inducing variegation. An alternative explanation consistent with our results is that the mosaic expression is a semi-autonomous characteristic of these transgene loci. Transgene-expressing and non-expressing cells differed in their ability to grow and be cloned in vitro, indicating that cellular differentiation affected the chromatin structure of the transgene locus on the Y. Karyotype analysis of male mice with the Y-linked transgene and from control male mice carrying the human HPRT transgene, or the mouse Pgk-1 gene at autosomal sites, indicated that the transgene-carrying Y is prone to non-disjunction, generating cells with two (or more) or no Y chromosomes in equal proportion. Further studies will determine if the propensity of this Y chromosome to mitotic errors is also observed in vivo.
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Affiliation(s)
- D D Pravtcheva
- Pediatric Research Institute, St. Louis University School of Medicine, Missouri 63110
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Graves JA, Foster JW. Evolution of mammalian sex chromosomes and sex-determining genes. INTERNATIONAL REVIEW OF CYTOLOGY 1994; 154:191-259. [PMID: 8083032 DOI: 10.1016/s0074-7696(08)62200-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- J A Graves
- Department of Genetics and Human Variation, LaTrobe University
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Disteche CM, Brannan CI, Larsen A, Adler DA, Schorderet DF, Gearing D, Copeland NG, Jenkins NA, Park LS. The human pseudoautosomal GM-CSF receptor alpha subunit gene is autosomal in mouse. Nat Genet 1993; 1:333-6. [PMID: 1363815 DOI: 10.1038/ng0892-333] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The gene encoding the granulocyte macrophage colony stimulating factor receptor alpha subunit (CSF2RA) has previously been mapped to the pseudoautosomal region of the human sex chromosomes. In contrast, we report that the murine locus, Csf2ra, maps to an autosome in the laboratory mouse. By in situ hybridization and genetic mapping, Csf2ra maps at telomeric band D2 of mouse chromosome 19. This first instance of a pseudoautosomal locus in human being autosomal in mouse, indicates incomplete conservation between the human and mouse X chromosomes and suggests that the genetic content of the pseudoautosomal region may differ between species of eutherian mammals due to chromosomal rearrangements.
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Affiliation(s)
- C M Disteche
- Department of Pathology, University of Washington, Seattle 98195
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Salido EC, Passage MB, Yen PH, Shapiro LJ, Mohandas TK. An evaluation of the inactive mouse X chromosome in somatic cell hybrids. SOMATIC CELL AND MOLECULAR GENETICS 1993; 19:65-71. [PMID: 8460399 DOI: 10.1007/bf01233955] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The expression of mouse Zfx, Rps4, Ube1x, and Xist was evaluated in hamster-mouse somatic cell hybrids containing either an active or an inactive mouse X chromosome using polymerase chain reaction of reverse transcribed RNA (RT-PCR). The results showed that Zfx, Rps4, and Ube1x are expressed exclusively from the active mouse X, while Xist is expressed exclusively from the inactive X. These findings confirm the pattern of X inactivation for these mouse genes reported previously based on expression in somatic tissues of F1 females from interspecific crosses. These results demonstrate the existence of differences between human and mouse X inactivation, as the corresponding human genes, ZFX, RPS4X, and UBE1 escape X inactivation.
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Affiliation(s)
- E C Salido
- Department of Pediatrics, University of California, San Francisco 94143
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Wu H, Fässler R, Schnieke A, Barker D, Lee KH, Chapman V, Francke U, Jaenisch R. An X-linked human collagen transgene escapes X inactivation in a subset of cells. Development 1992; 116:687-95. [PMID: 1289060 DOI: 10.1242/dev.116.3.687] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Transgenic mice carrying one complete copy of the human alpha 1(I) collagen gene on the X chromosome (HucII mice) were used to study the effect of X inactivation on transgene expression. By chromosomal in situ hybridization, the transgene was mapped to the D/E region close to the Xce locus, which is the controlling element. Quantitative RNA analyses indicated that transgene expression in homozygous and heterozygous females was about 125% and 62%, respectively, of the level found in hemizygous males. Also, females with Searle's translocation carrying the transgene on the inactive X chromosome (Xi) expressed about 18% transgene RNA when compared to hemizygous males. These results were consistent with the transgene being subject to but partially escaping from X inactivation. Two lines of evidence indicated that the transgene escaped X inactivation or was reactivated in a small subset of cells rather than being expressed at a lower level from the Xi in all cells, (i) None of nine single cell clones carrying the transgene on the Xi transcribed transgene RNA. In these clones the transgene was highly methylated in contrast to clones carrying the transgene on the Xa. (ii) In situ hybridization to RNA of cultured cells revealed that about 3% of uncloned cells with the transgene on the Xi expressed transgene RNA at a level comparable to that on the Xa. Our results indicate that the autosomal human collagen gene integrated on the mouse X chromosome is susceptible to X inactivation. Inactivation is, however, not complete as a subset of cells carrying the transgene on Xi expresses the transgene at a level comparable to that when carried on Xa.
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Affiliation(s)
- H Wu
- Whitehead Institute for Biomedical Research, Nine Cambridge Center, MA 02142
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12
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Abstract
In mammals, dosage compensation for X-linked genes between males and females is achieved by the inactivation of one of the X chromosomes in females. The inactivation event occurs early in development in all cells of the female mouse embryo and is stable and heritable in somatic cells. However, in the primordial germ cells, reactivation occurs around the time of meiosis. Owing to random inactivation in somatic cells, all female mice and humans are mosaic for X-linked gene function. Variable mosaicism can result in expression of disease in human females heterozygous for an X-linked gene defect. In the extra-embryonic lineages of female mouse embryos, and in the somatic cells of female marsupials, the paternally inherited X chromosome is preferentially inactivated. The X chromosomes in the egg and sperm must be differentially marked or imprinted, so that they are distinguished by the inactivation mechanism in these tissues. Initiation of inactivation of an entire X chromosome appears to spread from a single X-inactivation centre and may involve the recently discovered gene, XIST, which is expressed only from the inactive X chromosome. The maintenance of inactivation of certain household genes on the inactive X chromosome involves methylation of CpG islands in their 5' regions. Critical CpG sites are methylated at, or very close to, the time of inactivation in development. The mouse and the human X chromosomes carry the same genes but their arrangement is different and there are some genes in the pairing segment and elsewhere on the human X chromosome which can escape inactivation. Regions of homology between the mouse and human X chromosomes allow prediction of the map positions of homologous genes and provide mouse models of genetic disease in the human.
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Affiliation(s)
- M Monk
- MRC Mammalian Development Unit, London, UK
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13
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Affiliation(s)
- S M Gartler
- Department of Medicine, University of Washington, Seattle
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Raman R, Das P. Mammalian sex chromosomes. III. Activity of pseudoautosomal steroid sulfatase enzyme during spermatogenesis in Mus musculus. SOMATIC CELL AND MOLECULAR GENETICS 1991; 17:429-33. [PMID: 1763383 DOI: 10.1007/bf01233166] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Parallel to the inactivation of the X chromosome in somatic cells of female, the male X in mammals is rendered inactive during spermatogenesis. Pseudoautosomal genes, those present on the X-Y meiotically pairable region of male, escape inactivation in female soma. It is suggested, but not demonstrated, that they may also be refractory to the inactivation signal in male germ cells. We have assayed activity of the enzyme steroid sulfatase, product of a pseudoautosomal gene, in testicular cells of the mouse and shown its presence in premeiotic, meiotic (pachytene), and postmeiotic (spermatid) cell types. It appears that, as in females, pseudoautosomal genes may escape inactivation in male germ cells also.
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Affiliation(s)
- R Raman
- Department of Zoology, Banaras Hindu University, Varanasi, India
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Borsani G, Tonlorenzi R, Simmler MC, Dandolo L, Arnaud D, Capra V, Grompe M, Pizzuti A, Muzny D, Lawrence C, Willard HF, Avner P, Ballabio A. Characterization of a murine gene expressed from the inactive X chromosome. Nature 1991; 351:325-9. [PMID: 2034278 DOI: 10.1038/351325a0] [Citation(s) in RCA: 414] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
In mammals, equal dosage of gene products encoded by the X chromosome in male and female cells is achieved by X inactivation. Although X-chromosome inactivation represents the most extensive example known of long range cis gene regulation, the mechanism by which thousands of genes on only one of a pair of identical chromosomes are turned off is poorly understood. We have recently identified a human gene (XIST) exclusively expressed from the inactive X chromosome. Here we report the isolation and characterization of its murine homologue (Xist) which localizes to the mouse X inactivation centre region and is the first murine gene found to be expressed from the inactive X chromosome. Nucleotide sequence analysis indicates that Xist may be associated with a protein product. The similar map positions and expression patterns for Xist in mouse and man suggest that this gene may have a role in X inactivation.
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Affiliation(s)
- G Borsani
- Department of Cell Biology, Baylor College of Medicine, Houston, Texas 77030
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