PR-SET7 and SUV4-20H regulate H4 lysine-20 methylation at imprinting control regions in the mouse

Imprinted genes are important in development and their allelic expression is mediated by imprinting control regions (ICRs). On their DNA-methylated allele, ICRs are marked by trimethylation at H3 Lys 9 (H3K9me3) and H4 Lys 20 (H4K20me3), similar to pericentric heterochromatin. Here, we investigate which histone methyltransferases control this methylation of histone at ICRs. We found that inactivation of SUV4-20H leads to the loss of H4K20me3 and increased levels of its substrate, H4K20me1. H4K20me1 is controlled by PR-SET7 and is detected on both parental alleles. The disruption of SUV4-20H or PR-SET7 does not affect methylation of DNA at ICRs but influences precipitation of H3K9me3, which is suggestive of a trans-histone change. Unlike at pericentric heterochromatin, however, H3K9me3 at ICRs does not depend on SUV39H. Our data show not only new similarities but also differences between ICRs and heterochromatin, both of which show constitutive maintenance of methylation of DNA in somatic cells

R-spondin1 and FOXL2 act into two distinct cellular types during goat ovarian differentiation

<p>Abstract</p> <p>Background</p> <p>Up to now, two loci have been involved in XX sex-reversal in mammals following loss-of-function mutations, PIS (Polled Intersex Syndrome) in goats and <it>R-spondin1 </it>(<it>RSPO1</it>) in humans. Here, we analyze the possible interaction between these two factors during goat gonad development. Furthermore, since functional redundancy between different <it>R-spondins </it>may influence gonad development, we also studied the expression patterns of <it>RSPO2, 3 </it>and <it>4</it>.</p> <p>Results</p> <p>Similarly to the mouse, <it>RSPO1 </it>shows a sex-dimorphic expression pattern during goat gonad development with higher levels in the ovaries. Interestingly, the PIS mutation does not seem to influence its level of expression. Moreover, using an RSPO1 specific antibody, the RSPO1 protein was localized in the cortical area of early differentiating ovaries (36 and 40 d<it>pc</it>). This cortical area contains the majority of germ cell that are surrounded by FOXL2 negative somatic cells. At latter stages (50 and 60 d<it>pc</it>) RSPO1 protein remains specifically localized on the germ cell membranes. Interestingly, a time-specific relocation of RSPO1 on the germ cell membrane was noticed, moving from a uniform distribution at 40 d<it>pc </it>to a punctuated staining before and during meiosis (50 and 60 d<it>pc </it>respectively). Interestingly, also <it>RSPO2 </it>and <it>RSPO4 </it>show a sex-dimorphic expression pattern with higher levels in the ovaries. Although <it>RSPO4 </it>was found to be faintly and belatedly expressed, the expression of <it>RSPO2 </it>increases at the crucial 36 d<it>pc </it>stage, as does that of <it>FOXL2</it>. Importantly, <it>RSPO2 </it>expression appears dramatically decreased in XX PIS^-/-gonads at all three tested stages (36, 40 and 50 d<it>pc</it>).</p> <p>Conclusion</p> <p>During goat ovarian development, the pattern of expression of <it>RSPO1 </it>is in agreement with its possible anti-testis function but is not influenced by the PIS mutation. Moreover, our data suggest that RSPO1 may be associated with germ cell development and meiosis. Interestingly, another RSPO gene, RSPO2 shows a sex-dimorphic pattern of expression that is dramatically influenced by the PIS mutation.</p

FOXL2 is a Progesterone Target Gene in the Endometrium of Ruminants

Forkhead Box L2 (FOXL2) is a member of the FOXL class of transcription factors, which are essential for ovarian differentiation and function. In the endometrium, FOXL2 is also thought to be important in cattle; however, it is not clear how its expression is regulated. The maternal recognition of pregnancy signal in cattle, interferon-Tau, does not regulate FOXL2 expression. Therefore, in the present study, we examined whether the ovarian steroid hormones that orchestrate implantation regulate FOXL2 gene expression in ruminants. In sheep, we confirmed that FOXL2 mRNA and protein was expressed in the endometrium across the oestrous cycle (day 4 to day 15 post-oestrus). Similar to the bovine endometrium, ovine FOXL2 endometrial expression was low during the luteal phase of the oestrous cycle (4 to 12 days post-oestrus) and at implantation (15 days post-oestrus) while mRNA and protein expression significantly increased during the luteolytic phase (day 15 post-oestrus in cycle). In pregnant ewes, inhibition of progesterone production by trilostane during the day 5 to 16 period prevented the rise in progesterone concentrations and led to a significant increase of FOXL2 expression in caruncles compared with the control group (1.4-fold, p < 0.05). Ovariectomized ewes or cows that were supplemented with exogenous progesterone for 12 days or 6 days, respectively, had lower endometrial FOXL2 expression compared with control ovariectomized females (sheep, mRNA, 1.8-fold; protein, 2.4-fold; cattle; mRNA, 2.2-fold; p < 0.05). Exogenous oestradiol treatments for 12 days in sheep or 2 days in cattle did not affect FOXL2 endometrial expression compared with control ovariectomized females, except at the protein level in both endometrial areas in the sheep. Moreover, treating bovine endometrial explants with exogenous progesterone for 48h reduced FOXL2 expression. Using in vitro assays with COS7 cells we also demonstrated that progesterone regulates the FOXL2 promoter activity through the progesterone receptor. Collectively, our findings imply that endometrial FOXL2 is, as a direct target of progesterone, involved in early pregnancy and implantation

Foxl2 gene and the development of the ovary : a story about goat, mouse, fish and woman

In this review, we describe recent results concerning the genetics of sex determination in mammals. Particularly, we developed the study of the FOXL2 gene and its implication in genetic anomalies in goats (PIS mutation) and humans (BPES). We present the expression of FOXL2 in the ovaries of different species

Novel Insights into the Bovine Polled Phenotype and Horn Ontogenesis in Bovidae

Despite massive research efforts, the molecular etiology of bovine polledness and the developmental pathways involved in horn ontogenesis are still poorly understood. In a recent article, we provided evidence for the existence of at least two different alleles at the Polled locus and identified candidate mutations for each of them. None of these mutations was located in known coding or regulatory regions, thus adding to the complexity of understanding the molecular basis of polledness. We confirm previous results here and exhaustively identify the causative mutation for the Celtic allele (PC) and four candidate mutations for the Friesian allele (PF). We describe a previously unreported eyelash-and-eyelid phenotype associated with regular polledness, and present unique histological and gene expression data on bovine horn bud differentiation in fetuses affected by three different horn defect syndromes, as well as in wild-type controls. We propose the ectopic expression of a lincRNA in PC/p horn buds as a probable cause of horn bud agenesis. In addition, we provide evidence for an involvement of OLIG2, FOXL2 and RXFP2 in horn bud differentiation, and draw a first link between bovine, ovine and caprine Polled loci. Our results represent a first and important step in understanding the genetic pathways and key process involved in horn bud differentiation in Bovidae

Détermination du Sexe, Différenciation de la Lignée Germinale, Epigénétique et Fertilité

In mammals, the fertility of an individual, as well as the transmission to its offspring of quality genetic and epigenetic information, are closely linked to the smooth running of the differentiation of the gonads and in particular of the germ line. In the gonads, a harmonious dialogue between germ cells and their surrounding somatic cells is essential and begins in fetal life after sex determination and the initiation of ovarian or testicular differentiation. During my work and that of the students I supervised, I became interested in the genetic cascades involved in the determination and differentiation of the testicle and the ovary in farm animals. In parallel, I have developed in recent years several projects on male and female germ lines; focusing, particularly in the male, on the differentiation of germ cells and the reprogramming of their epigenome.Chez les mammifères, la fertilité d’un individu ainsi que la transmission à sa descendance d’informations génétiques et épigénétiques de qualité, sont intimement liées au bon déroulement de la différenciation des gonades et en particulier de la lignée germinale. Dans les gonades, un dialogue harmonieux entre les cellules germinales et leurs cellules somatiques environnantes est indispensable et débute dès la vie fœtale après la détermination du sexe et l’initiation de la différenciation de l’ovaire ou du testicule. Au cours de mes travaux et ceux des étudiantes que j’ai encadrées, je me suis intéressée aux cascades génétiques impliquées dans la détermination et la différenciation du testicule et de l’ovaire chez des animaux d’élevage. En parallèle, j’ai développé ces dernières années plusieurs projets sur les lignées germinales mâle et femelle ; en me concentrant, en particulier chez le mâle, sur la différenciation des cellules germinales et la reprogrammation de leur épigénome

Détermination du Sexe, Différenciation de la Lignée Germinale, Epigénétique et Fertilité

In mammals, the fertility of an individual, as well as the transmission to its offspring of quality genetic and epigenetic information, are closely linked to the smooth running of the differentiation of the gonads and in particular of the germ line. In the gonads, a harmonious dialogue between germ cells and their surrounding somatic cells is essential and begins in fetal life after sex determination and the initiation of ovarian or testicular differentiation. During my work and that of the students I supervised, I became interested in the genetic cascades involved in the determination and differentiation of the testicle and the ovary in farm animals. In parallel, I have developed in recent years several projects on male and female germ lines; focusing, particularly in the male, on the differentiation of germ cells and the reprogramming of their epigenome.Chez les mammifères, la fertilité d’un individu ainsi que la transmission à sa descendance d’informations génétiques et épigénétiques de qualité, sont intimement liées au bon déroulement de la différenciation des gonades et en particulier de la lignée germinale. Dans les gonades, un dialogue harmonieux entre les cellules germinales et leurs cellules somatiques environnantes est indispensable et débute dès la vie fœtale après la détermination du sexe et l’initiation de la différenciation de l’ovaire ou du testicule. Au cours de mes travaux et ceux des étudiantes que j’ai encadrées, je me suis intéressée aux cascades génétiques impliquées dans la détermination et la différenciation du testicule et de l’ovaire chez des animaux d’élevage. En parallèle, j’ai développé ces dernières années plusieurs projets sur les lignées germinales mâle et femelle ; en me concentrant, en particulier chez le mâle, sur la différenciation des cellules germinales et la reprogrammation de leur épigénome

La différenciation du sexe: Acquis et perspectives

Nos connaissances de la différenciation du sexe chez les mammifères ont considérablement évolué depuis les deux dernières décennies et la découverte du déterminant testiculaire. Les processus morphogénétiques impliqués dans la différenciation des gonades mâles et femelles et les principaux gènes majeurs sous-jacents sont présentés dans cet article. Un accent particulier est mis sur les différences existantes entre le modèle murin de référence et les autres mammifères, notamment l’homme et la chèvre.Our knowledge on sex differentiation in mammals has considerably progressed during the last decennials, beginning with the discovery of the testis-determining factor. Here, the morphogenetic processes involved in the early gonadic switch will be presented, together with the major genes involved in testis and ovary formation. Existing differences between the widely used mouse model and other mammals, such as human and goat, will be highlighted

Conservation, rôle et régulation de FOXL2, un facteur clef de la différenciation ovarienne impliqué dans le syndrome PIS (Polled Intersex Syndrome), chez la chèvre

PIS (Polled Intersex Syndrome) mutation in goat induces a syndrome characterized by hornless, as soon as the heterozygous state, and female-to-male sex-reversal (XX males) when homozygous. The mutation responsible for PIS syndrome consists in a deletion of a 11.7kb region (called PIS region) that does not contain any coding sequences. The PIS region is required for the expression of at least 3 genes located at a long distance from this regulatory region: PISRT1 located at 35kb and FOXL2 and PFOXic located at more than 300kb. These 3 genes present a sex-dimorphic expression as they are strongly expressed in the developing ovary since the earliest stages of gonad differentiation. When PIS is homozygously deleted in XX gonads, expression of the 3 genes is lost, inducing the up-regulation of male specific genes, leading to testis development. One gene of the PIS locus, FOXL2 (Forkhead box L 2), is a highly conserved transcription factor within vertebrates. Thus, we focused on this gene: we described (i) its structural and expressional conservation in chicken, (ii) one of its targets during early ovarian development (CYP19) and (iii) its particular proximal regulation (bi-directional promoter). Moreover, conservation studies of the PIS locus in mouse lead us to propose the existence of two different models of sex determination with mouse slightly different from other mammals.Chez la chèvre la mutation PIS (Polled Intersex Syndrome) est responsable de la survenue d'un syndrome qui associe, dès l'hétérozygotie, une absence de cornes chez les animaux des deux sexes, à une inversion du sexe femelle vers mâle chez les animaux XX porteurs de cette même mutation, mais à l'état homozygote (mâles XX). La mutation responsable du syndrome PIS consiste en une délétion d'une région de 11.7kb (région PIS) qui ne contient pas de séquence transcrite. Cette région PIS est cependant nécessaire à l'expression transcriptionelle d'au moins 3 gènes situés à longue distance: PISRT1 situé à 35kb et FOXL2 et PFOXic situés à plus de 300kb. Ces 3 gènes présentent une expression sexuellement dimorphique puisqu'ils sont très fortement exprimés dans l'ovaire depuis les premiers stades de différenciation jusqu'à l'âge adulte. Lorsque la région PIS est délétée de façon homozygote chez un animal XX, l'expression de ces trois gènes est perdue dans la gonade en développement, conduisant à la différenciation de testicules. Parmi les gènes, régulés par la région PIS, FOXL2 (Forkhead box L 2) code pour un facteur de transcription très conservé parmi les différentes espèces de vertébrés. Ainsi nous nous sommes particulièrement intéressés à ce gène et nous avons décrit (i) sa conservation chez le poulet, (ii) l'une de ses cibles dans l'ovaire de chèvre (CYP19) et (iii) son mode de régulation particulier (existence d'un promoteur bidirectionnel). Enfin, l'étude de la conservation des gènes du locus PIS chez la souris nous a conduit à proposer l'hypothèse de l'existence de deux modèles de détermination du sexe différents entre la souris et les autres mammifères.VERSAILLES-BU Sciences et IUT (786462101) / SudocSudocFranceF