Bernhard G Herrmann

Max Planck Institute for Molecular Genetics, Berlín, Berlin, Germany

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Publications (57)472.03 Total impact

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    ABSTRACT: Supplementary information available for this article at http://www.nature.com/ncomms/2014/140908/ncomms5675/suppinfo/ncomms5675_S1.html
    Nat Commun. 09/2014; 5.
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    ABSTRACT: Colon cancer cells frequently carry mutations that activate the β-catenin and mitogen-activated protein kinase (MAPK) signaling cascades. Yet how oncogenic alterations interact to control cellular hierarchies during tumor initiation and progression is largely unknown. We found that oncogenic BRAF modulates gene expression associated with cell differentiation in colon cancer cells. We therefore engineered a mouse with an inducible oncogenic BRAF transgene, and analyzed BRAF effects on cellular hierarchies in the intestinal epithelium in vivo and in primary organotypic culture. We demonstrate that transgenic expression of oncogenic BRAF in the mouse strongly activated MAPK signal transduction, resulted in the rapid development of generalized serrated dysplasia, but unexpectedly also induced depletion of the intestinal stem cell (ISC) pool. Histological and gene expression analyses indicate that ISCs collectively converted to short-lived progenitor cells after BRAF activation. As Wnt/β-catenin signals encourage ISC identity, we asked whether β-catenin activity could counteract oncogenic BRAF. Indeed, we found that intestinal organoids could be partially protected from deleterious oncogenic BRAF effects by Wnt3a or by small-molecule inhibition of GSK3β. Similarly, transgenic expression of stabilized β-catenin in addition to oncogenic BRAF partially prevented loss of stem cells in the mouse intestine. We also used BRAF(V637E) knock-in mice to follow changes in the stem cell pool during serrated tumor progression and found ISC marker expression reduced in serrated hyperplasia forming after BRAF activation, but intensified in progressive dysplastic foci characterized by additional mutations that activate the Wnt/β-catenin pathway. Our study suggests that oncogenic alterations activating the MAPK and Wnt/β-catenin pathways must be consecutively and coordinately selected to assure stem cell maintenance during colon cancer initiation and progression. Notably, loss of stem cell identity upon induction of BRAF/MAPK activity may represent a novel fail-safe mechanism protecting intestinal tissue from oncogene activation.Oncogene advance online publication, 11 August 2014; doi:10.1038/onc.2014.247.
    Oncogene 08/2014; · 8.56 Impact Factor
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    ABSTRACT: Differential gene expression is a prerequisite for the formation of multiple cell types from the fertilized egg during embryogenesis. Understanding the gene regulatory networks controlling cellular differentiation requires the identification of crucial differentially expressed control genes and, ideally, the determination of the complete transcriptomes of each individual cell type. Here, we have analyzed the transcriptomes of six major tissues dissected from mid-gestational (TS12) mouse embryos. Approximately one billion reads derived by RNA-seq analysis provided extended transcript lengths, novel first exons and alternative transcripts of known genes. We have identified 1375 genes showing tissue-specific expression, providing gene signatures for each of the six tissues. In addition, we have identified 1403 novel putative long noncoding RNA gene loci, 439 of which show differential expression. Our analysis provides the first complete transcriptome data for the mouse embryo. It offers a rich data source for the analysis of individual genes and gene regulatory networks controlling mid-gestational development.
    Development 05/2014; · 6.60 Impact Factor
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    ABSTRACT: Background Classic bladder exstrophy (CBE) is the most common form of the bladder exstrophy and epispadias complex. Previously, we and others have identified four patients with a duplication of 22q11.21 among a total of 96 unrelated CBE patients.Methods Here, we investigated whether this chromosomal aberration was commonly associated with CBE/bladder exstrophy and epispadias complex in an extended case-control sample. Multiplex ligation-dependent probe amplification and microarray-based analysis were used to identify 22q11.21 duplications in 244 unrelated bladder exstrophy and epispadias complex patients (including 217 CBE patients) and 665 healthy controls.ResultsNew duplications of variable size were identified in four CBE patients and one control. Pooling of our previous and present data (eight duplications in 313 CBE patients) yielded a combined odds ratio of 31.86 (95% confidence interval, 4.24–1407.97). Array-based sequence capture and high-throughput targeted re-sequencing established that all breakpoints resided within the low-copy repeats 22A to 22D. Comparison of the eight duplications revealed a 414 kb phenocritical region harboring 12 validated RefSeq genes. Characterization of these 12 candidate genes through whole-mount in situ hybridization of mouse embryos at embryonic day 9.5 suggested that CRKL, THAP7, and LZTR1 are CBE candidate genes.Conclusion Our data suggest that duplication of 22q11.21 increases CBE risk and implicate a phenocritical region in disease formation. Birth Defects Research (Part A), 2014. © 2014 Wiley Periodicals, Inc.
    Birth Defects Research Part A Clinical and Molecular Teratology 04/2014; · 2.27 Impact Factor
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    ABSTRACT: Mesoderm formation in the mouse embryo initiates around E6.5 at the primitive streak and continues until the end of axis extension at E12.5. It requires the process of epithelial-to-mesenchymal transition (EMT), wherein cells detach from the epithelium, adopt mesenchymal cell morphology, and gain competence to migrate. It was shown previously that, prior to mesoderm formation, the transcription factor SRF (Serum Response Factor) is essential for the formation of the primitive streak. To elucidate the role of murine Srf in mesoderm formation during axis extension we conditionally inactivated Srf in nascent mesoderm using the T(s)::Cre driver mouse. Defects in mutant embryos became apparent at E8.75 in the heart and in the allantois. From E9.0 onwards body axis elongation was arrested. Using genome-wide expression analysis, combined with SRF occupancy data from ChIP-seq analysis, we identified a set of direct SRF target genes acting in posterior nascent mesoderm which are enriched for transcripts associated with migratory function. We further show that cell migration is impaired in Srf mutant embryos. Thus, the primary role for SRF in the nascent mesoderm during elongation of the embryonic body axis is the activation of a migratory program, which is a prerequisite for axis extension.
    Mechanisms of Development. 01/2014;
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    ABSTRACT: Congenital abnormalities of the kidney and urinary tract (CAKUT) account for approximately half of children with chronic kidney disease and they are the most frequent cause of end-stage renal disease in children in the US. However, its genetic etiology remains mostly elusive. VACTERL association is a rare disorder that involves congenital abnormalities in multiple organs including the kidney and urinary tract in up to 60% of the cases. By homozygosity mapping and whole-exome resequencing combined with high-throughput mutation analysis by array-based multiplex PCR and next-generation sequencing, we identified recessive mutations in the gene TNF receptor-associated protein 1 (TRAP1) in two families with isolated CAKUT and three families with VACTERL association. TRAP1 is a heat-shock protein 90-related mitochondrial chaperone possibly involved in antiapoptotic and endoplasmic reticulum stress signaling. Trap1 is expressed in renal epithelia of developing mouse kidney E13.5 and in the kidney of adult rats, most prominently in proximal tubules and in thick medullary ascending limbs of Henle's loop. Thus, we identified mutations in TRAP1 as highly likely causing CAKUT or VACTERL association with CAKUT.Kidney International advance online publication, 23 October 2013; doi:10.1038/ki.2013.417.
    Kidney International 10/2013; · 8.52 Impact Factor
  • Phillip Grote, Bernhard G Herrmann
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    ABSTRACT: Epigenetic control mechanisms determine active and silenced regions of the genome. It is known that the Polycomb Repressive Complex 2 (PRC2) and the Trithorax group/Mixed lineage leukemia (TrxG/Mll) complex are able to set repressive and active histone marks, respectively. Long non-coding RNAs (lncRNAs) can interact with either of these complexes and guide them to regulatory elements, thereby modifying the expression levels of target genes. The lncRNA Fendrr is transiently expressed in lateral mesoderm of mid-gestational mouse embryos and was shown to interact with both PRC2 and TrxG/Mll complexes in vivo. Gene targeting revealed that loss of Fendrr results in impaired differentiation of tissues derived from lateral mesoderm, the heart and the body wall, ultimately leading to embryonic death. Molecular data suggests that Fendrr acts via dsDNA/RNA triplex formation at target regulatory elements, and directly increases PRC2 occupancy at these sites. This, in turn, modifies the ratio of repressive to active marks, adjusting the expression levels of Fendrr target genes in lateral mesoderm. We propose that Fendrr also mediates long-term epigenetic marks to define expression levels of its target genes within the descendants of lateral mesoderm cells. Here we discuss approaches for lncRNA gene knockouts in the mouse, and suggest a model how Fendrr and possibly other lncRNAs act during embryogenesis.
    RNA biology 08/2013; 10(10). · 5.56 Impact Factor
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    ABSTRACT: The acronym VATER/VACTERL association describes the combination of at least three of the following congenital anomalies: vertebral defects (V), anorectal malformations (A), cardiac defects (C), tracheoesophageal fistula with or without esophageal atresia (TE), renal malformations (R), and limb defects (L). We aimed to identify highly penetrant de novo copy number variations (CNVs) that contribute to VATER/VACTERL association. Array-based molecular karyotyping was performed in a cohort of 41 patients with VATER/VACTERL association and 6 patients with VATER/VACTERL-like phenotype including all of the patients' parents. Three de novo CNVs were identified involving chromosomal regions 1q41, 2q37.3, and 8q24.3 comprising one (SPATA17), two (CAPN10, GPR35), and three (EPPK1, PLEC, PARP10) genes, respectively. Pre-existing data from the literature prompted us to choose GPR35 and EPPK1 for mouse expression studies. Based on these studies, we prioritized GPR35 for sequencing analysis in an extended cohort of 192 patients with VATER/VACTERL association and VATER/VACTERL-like phenotype. Although no disease-causing mutation was identified, our mouse expression studies suggest GPR35 to be involved in the development of the VATER/VACTERL phenotype. Follow-up of GPR35 and the other genes comprising the identified duplications is warranted.European Journal of Human Genetics advance online publication, 3 April 2013; doi:10.1038/ejhg.2013.58.
    European journal of human genetics: EJHG 04/2013; · 3.56 Impact Factor
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    ABSTRACT: Aberrant CpG methylation is a universal epigenetic trait of cancer cell genomes. However, human cancer samples or cell lines preclude the investigation of epigenetic changes occurring early during tumour development. Here, we have used MeDIP-seq to analyse the DNA methylome of APC(Min) adenoma as a model for intestinal cancer initiation, and we present a list of more than 13,000 recurring differentially methylated regions (DMRs) characterizing intestinal adenoma of the mouse. We show that Polycomb Repressive Complex (PRC) targets are strongly enriched among hypermethylated DMRs, and several PRC2 components and DNA methyltransferases were up-regulated in adenoma. We further demonstrate by bisulfite pyrosequencing of purified cell populations that the DMR signature arises de novo in adenoma cells rather than by expansion of a pre-existing pattern in intestinal stem cells or undifferentiated crypt cells. We found that epigenetic silencing of tumour suppressors, which occurs frequently in colon cancer, was rare in adenoma. Quite strikingly, we identified a core set of DMRs, which is conserved between mouse adenoma and human colon cancer, thus possibly revealing a global panel of epigenetically modified genes for intestinal tumours. Our data allow a distinction between early conserved epigenetic alterations occurring in intestinal adenoma and late stochastic events promoting colon cancer progression, and may facilitate the selection of more specific clinical epigenetic biomarkers.
    PLoS Genetics 02/2013; 9(2):e1003250. · 8.52 Impact Factor
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    ABSTRACT: BACKGROUND: The exstrophy-epispadias complex (BEEC) is a urogenital birth defect of varying severity. The causes of the BEEC are likely to be heterogeneous, with individual environmental or genetic risk factors still being largely unknown. In this study, we aimed to identify de novo causative copy number variations (CNVs) that contribute to the BEEC. METHODS Array-based molecular karyotyping was performed to screen 110 individuals with BEEC. Promising CNVs were tested for de novo occurrence by investigating parental DNAs. Genes located in regions of rearrangements were prioritized through expression analysis in mice to be sequenced in the complete cohort, to identify high-penetrance mutations involving small sequence changes. RESULTS A de novo 0.9 Mb microduplication involving chromosomal region 19p13.12 was identified in a single patient. This region harbors 20 validated RefSeq genes, and in situ hybridization data showed specific expression of the Wiz gene in regions surrounding the cloaca and the rectum between GD 9.5 and 13.5. Sanger sequencing of the complete cohort did not reveal any pathogenic alterations affecting the coding region of WIZ. CONCLUSIONS The present study suggests chromosomal region 19p13.12 as possibly involved in the development of CBE, but further studies are needed to prove a causal relation. The spatiotemporal expression patterns determined for the genes encompassed suggest a role for Wiz in the development of the phenotype. Our mutation screening, however, could not confirm that WIZ mutations are a frequent cause of CBE, although rare mutations might be detectable in larger patient samples. 19p13.12, microduplication, bladder exstrophy-epispadias complex, array-based molecular karyotyping, in situ hybridization analysis, copy number variations, WIZ Birth Defects Research (Part A), 2013. © 2013 Wiley Periodicals, Inc.
    Birth Defects Research Part A Clinical and Molecular Teratology 01/2013; · 2.27 Impact Factor
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    ABSTRACT: The histone-modifying complexes PRC2 and TrxG/MLL play pivotal roles in determining the activation state of genes controlling pluripotency, lineage commitment, and cell differentiation. Long noncoding RNAs (lncRNAs) can bind to either complex, and some have been shown to act as modulators of PRC2 or TrxG/MLL activity. Here we show that the lateral mesoderm-specific lncRNA Fendrr is essential for proper heart and body wall development in the mouse. Embryos lacking Fendrr displayed upregulation of several transcription factors controlling lateral plate or cardiac mesoderm differentiation, accompanied by a drastic reduction in PRC2 occupancy along with decreased H3K27 trimethylation and/or an increase in H3K4 trimethylation at their promoters. Fendrr binds to both the PRC2 and TrxG/MLL complexes, suggesting that it acts as modulator of chromatin signatures that define gene activity. Thus, we identified an lncRNA that plays an essential role in the regulatory networks controlling the fate of lateral mesoderm derivatives.
    Developmental Cell 01/2013; 24(2):206-214. · 12.86 Impact Factor
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    ABSTRACT: The T-box transcription factor BRACHYURY (T) is a key regulator of mesoderm formation during early development. Complete loss of T has been shown to lead to embryonic lethality around E10.0. Here we characterize an inducible miRNA-based in vivo knockdown mouse model of T, termed KD3-T, which exhibits a hypomorphic phenotype. KD3-T embryos display axial skeletal defects caused by apoptosis of paraxial mesoderm, which is accompanied by urorectal malformations resembling the murine uro-recto-caudal syndrome and human caudal regression syndrome phenotypes. We show that there is a reduction of T in the notochord of KD3-T embryos which results in impaired notochord differentiation and its subsequent loss, whereas levels of T in the tailbud are sufficient for axis extension and patterning. Furthermore, the notochord in KD3-T embryos adopts a neural character and loses its ability to act as a signaling center. Since KD3-T animals survive until birth, they are useful for examining later roles for T in the development of urorectal tissues.
    Developmental Biology 09/2012; 372(1):55-67. · 3.87 Impact Factor
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    ABSTRACT: The t-haplotype, a variant form of the t-complex region on mouse chromosome 17, acts as selfish genetic element and is transmitted at high frequencies (> 95%) from heterozygous (t/+) males to their offspring. This phenotype is termed transmission ratio distortion (TRD) and is caused by the interaction of the t-complex responder (Tcr) with several quantitative trait loci (QTL), the t-complex distorters (Tcd1 to Tcd4), all located within the t-haplotype region. Current data suggest that the distorters collectively impair motility of all sperm derived from t/+ males; t-sperm is rescued by the responder, whereas (+)-sperm remains partially dysfunctional. Recently we have identified two distorters as regulators of RHO small G proteins. Here we show that the nucleoside diphosphate kinase gene Nme3 acts as a QTL on TRD. Reduction of the Nme3 dosage by gene targeting of the wild-type allele enhanced the transmission rate of the t-haplotype and phenocopied distorter function. Genetic and biochemical analysis showed that the t-allele of Nme3 harbors a mutation (P89S) that compromises enzymatic activity of the protein and genetically acts as a hypomorph. Transgenic overexpression of the Nme3 t-allele reduced t-haplotype transmission, proving it to be a distorter. We propose that the NME3 protein interacts with RHO signaling cascades to impair sperm motility through hyperactivation of SMOK, the wild-type form of the responder. This deleterious effect of the distorters is counter-balanced by the responder, SMOK(Tcr), a dominant-negative protein kinase exclusively expressed in t-sperm, thus permitting selfish behaviour and preferential transmission of the t-haplotype. In addition, the previously reported association of NME family members with RHO signaling in somatic cell motility and metastasis, in conjunction with our data involving RHO signaling in sperm motility, suggests a functional conservation between mechanisms for motility control in somatic cells and spermatozoa.
    PLoS Genetics 03/2012; 8(3):e1002567. · 8.52 Impact Factor
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    ABSTRACT: Cellular hierarchies and signals that govern stemness and differentiation of intestinal adenoma cells are not well defined. In this study, we used organotypic culture to investigate the impact of β-catenin and BMP signals in cells that form intestinal adenoma in the mouse. We found that activation of β-catenin signaling by loss of APC or transgenic induction of oncogenic mutant β-catenin (Ctnnb1(mut) ) initiates the conversion of untransformed intestinal cells to tumor cells. These tumor cells display cancer stem cell (CSC) traits such as increased expression of the CSC markers Cd133 and Cd44, a high capacity for self-renewal and unlimited proliferative potential. Subsequent inactivation of transgenic Ctnnb1(mut) results in the reversion of tumor cells to normal intestinal stem cells, which immediately reinstall the cellular hierarchy of the normal intestinal epithelium. Our data demonstrate that oncogenic activation of β-catenin signaling initiates the early steps of intestinal cellular transformation in the absence of irreversible genetic or epigenetic changes. Interestingly, we found that tumor cells in culture and in adenoma produce BMP4, which counteracts CSC-like traits by initiating irreversible cellular differentiation and loss of self-renewal capacity. We conclude that the opposition of stemness-maintaining oncogenic β-catenin signals and autocrine differentiating BMP signals within the adenoma cell provides a rationale for the formation of cellular hierarchies in intestinal adenoma and may serve to limit adenoma growth.
    International Journal of Cancer 02/2012; 131(10):2242-52. · 6.20 Impact Factor
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    ABSTRACT: http://www.cambridge.org/gb/knowledge/isbn/item6687735/Evolution-of-the-House-Mouse/?site_locale=en_GB
    01/2012: pages 548; Cambridge University Press., ISBN: 9780521760669
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    ABSTRACT: In tumor cells, stepwise oncogenic deregulation of signaling cascades induces alterations of cellular morphology and promotes the acquisition of malignant traits. Here, we identified a set of 21 genes, including FGF9, as determinants of tumor cell morphology by an RNA interference phenotypic screen in SW480 colon cancer cells. Using a panel of small molecular inhibitors, we subsequently established phenotypic effects, downstream signaling cascades, and associated gene expression signatures of FGF receptor signals. We found that inhibition of FGF signals induces epithelial cell adhesion and loss of motility in colon cancer cells. These effects are mediated via the mitogen-activated protein kinase (MAPK) and Rho GTPase cascades. In agreement with these findings, inhibition of the MEK1/2 or JNK cascades, but not of the PI3K-AKT signaling axis also induced epithelial cell morphology. Finally, we found that expression of FGF9 was strong in a subset of advanced colon cancers, and overexpression negatively correlated with patients' survival. Our functional and expression analyses suggest that FGF receptor signals can contribute to colon cancer progression.
    PLoS ONE 01/2011; 6(8):e23381. · 3.53 Impact Factor
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    ABSTRACT: Functional analysis of multiple genes is key to understanding gene regulatory networks controlling embryonic development. We have developed an integrated vector system for inducible gene silencing by shRNAmir-mediated RNA interference in mouse embryos, as a fast method for dissecting mammalian gene function. For validation of the vector system, we generated mutant phenotypes for Brachyury, Foxa2 and Noto, transcription factors which play pivotal roles in embryonic development. Using a series of Brachyury shRNAmir vectors of various strengths we generated hypomorphic and loss of function phenotypes allowing the identification of Brachyury target genes involved in trunk development. We also demonstrate temporal control of gene silencing, thus bypassing early embryonic lethality. Importantly, off-target effects of shRNAmir expression were not detectable. Taken together, the system allows the dissection of gene function at unprecedented detail and speed, and provides tight control of the genetic background minimizing intrinsic variation.
    Nucleic Acids Research 03/2010; 38(11):e122. · 8.81 Impact Factor
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    ABSTRACT: Colorectal cancer (CRC) is with approximately 1 million cases the third most common cancer worldwide. Extensive research is ongoing to decipher the underlying genetic patterns with the hope to improve early cancer diagnosis and treatment. In this direction, the recent progress in next generation sequencing technologies has revolutionized the field of cancer genomics. However, one caveat of these studies remains the large amount of genetic variations identified and their interpretation. Here we present the first work on whole exome NGS of primary colon cancers. We performed 454 whole exome pyrosequencing of tumor as well as adjacent not affected normal colonic tissue from microsatellite stable (MSS) and microsatellite instable (MSI) colon cancer patients and identified more than 50,000 small nucleotide variations for each tissue. According to predictions based on MSS and MSI pathomechanisms we identified eight times more somatic non-synonymous variations in MSI cancers than in MSS and we were able to reproduce the result in four additional CRCs. Our bioinformatics filtering approach narrowed down the rate of most significant mutations to 359 for MSI and 45 for MSS CRCs with predicted altered protein functions. In both CRCs, MSI and MSS, we found somatic mutations in the intracellular kinase domain of bone morphogenetic protein receptor 1A, BMPR1A, a gene where so far germline mutations are associated with juvenile polyposis syndrome, and show that the mutations functionally impair the protein function. We conclude that with deep sequencing of tumor exomes one may be able to predict the microsatellite status of CRC and in addition identify potentially clinically relevant mutations.
    PLoS ONE 01/2010; 5(12):e15661. · 3.53 Impact Factor
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    ABSTRACT: The t complex responder (Tcr) encoded by the mouse t haplotype is able to cause phenotypic differences between t and + sperm derived from t/+ males, leading to non-Mendelian inheritance. This capability of Tcr contradicts the concept of phenotypic equivalence proposed for sperm cells, which develop in a syncytium and actively share gene products. By analyzing a Tcr minigene in hemizygous transgenic mice, we show that Tcr gene products are post-meiotically expressed and are retained in the haploid sperm cells. The wild-type allele of Tcr, sperm motility kinase-1 (Smok1), behaves in the same manner, suggesting that Tcr/Smok reveal a common mechanism prone to evolve non-Mendelian inheritance in mammals.
    Genes & development 12/2009; 23(23):2705-10. · 12.08 Impact Factor
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    ABSTRACT: The vertebral column and skeletal muscles of vertebrates are derived from the paraxial mesoderm, which is laid down initially as two stripes of mesenchymal cells alongside the neural tube and subsequently segmented. Previous work has shown that the wingless-type MMTV integration site family (WNT), fibroblast growth factor- and Delta-Notch signalling pathways control presomitic mesoderm (psm) formation and segmentation. Here, we show that the expression of mesogenin 1, a basic helix-loop-helix transcription factor, which is essential for psm maturation, is regulated by synergism between WNT signalling and the T-box 6 transcription factor, involving a feed-forward control mechanism. These findings emphasize the crucial role of WNT signalling in the control of psm formation, maturation and segmentation.
    EMBO Reports 09/2007; 8(8):784-9. · 7.19 Impact Factor

Publication Stats

4k Citations
472.03 Total Impact Points

Institutions

  • 2004–2014
    • Max Planck Institute for Molecular Genetics
      • Department of Developmental Genetics
      Berlín, Berlin, Germany
  • 2007–2013
    • Charité Universitätsmedizin Berlin
      • Institute of Medical Genetics and Human Genetics
      Berlin, Land Berlin, Germany
  • 1991–2003
    • Max Planck Institute for Developmental Biology
      • Department of Biochemistry
      Tübingen, Baden-Württemberg, Germany
    • MRC National Institute for Medical Research
      • Division of Developmental Biology
      London, ENG, United Kingdom
  • 1998–1999
    • Max Planck Institute of Immunobiology and Epigenetics
      Freiburg, Baden-Württemberg, Germany
  • 1996
    • University of Reading
      • Department of Animal Science
      Reading, ENG, United Kingdom