R Schuh

Max Planck Institute for Biophysical Chemistry, Göttingen, Lower Saxony, Germany

Are you R Schuh?

Claim your profile

Publications (44)335.75 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: The transition from a liquid to a gas filled tubular network is the prerequisite for normal function of vertebrate lungs and invertebrate tracheal systems. However, the mechanisms underlying the process of gas filling remain obscure. Here we show that waterproof, encoding a fatty acyl-CoA reductase (FAR), is essential for the gas filling of the tracheal tubes during Drosophila embryogenesis, and does not affect branch network formation or key tracheal maturation processes. However, electron microscopic analysis reveals that in waterproof mutant embryos the formation of the outermost tracheal cuticle sublayer, the envelope, is disrupted and the hydrophobic tracheal coating is damaged. Genetic and gain-of-function experiments indicate a non-cell-autonomous waterproof function for the beginning of the tracheal gas filling process. Interestingly, Waterproof reduces very long chain fatty acids of 24 and 26 carbon atoms to fatty alcohols. Thus, we propose that Waterproof plays a key role in tracheal gas filling by providing very long chain fatty alcohols that serve as potential substrates for wax ester synthesis or related hydrophobic substances that ultimately coat the inner lining of the trachea. The hydrophobicity in turn reduces the tensile strength of the liquid inside the trachea, leading to the formation of a gas bubble, the focal point for subsequent gas filling. Waterproof represents the first enzyme described to date that is necessary for tracheal gas filling without affecting branch morphology. Considering its conservation throughout evolution, Waterproof orthologues may play a similar role in the vertebrate lung.
    Developmental Biology 10/2013; · 3.87 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Claudins are integral transmembrane components of the tight junctions (TJs) forming trans-epithelial barriers in many organs, such as nervous system, lung and epidermis. In Drosophila three claudins have been identified, which are required for forming the TJs analogous structure - the septate junctions (SJs). The lack of claudins results in a disruption of SJs integrity leading to a breakdown of the trans-epithelial barrier and to disturbed epithelial morphogenesis. However, little is known about claudin partners for transport mechanisms and membrane organization. Here we present a comprehensive analysis of the claudin proteome in Drosophila by combining biochemical and physiological approaches. Using specific antibodies against the claudin Megatrachea for immunoprecipitation and mass spectrometry we identified 142 proteins associated with Megatrachea in embryos. The Megatrachea interacting proteins were analysed in vivo by tissue-specific knock-down of the corresponding genes using RNA interference. We identified known and novel putative SJs components, such as the gene product of CG3021. Furthermore, our data suggest that the control of secretion processes specific to SJs and dependent on Sec61p may involve Megatrachea interaction with Sec61 subunits. Also, our findings suggest that clathrin-coated vesicles may regulate Megatrachea turnover at the plasma membrane similar to human claudins. As claudins are conserved both in structure and function, our findings offer novel candidate proteins involved in the claudin interactome of vertebrates and invertebrates.
    Journal of Biological Chemistry 10/2012; 287:36756-36765.. · 4.65 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Claudins are integral transmembrane components of the tight junctions (TJs) forming trans-epithelial barriers in many organs, such as nervous system, lung and epidermis. In Drosophila three claudins have been identified, which are required for forming the TJs analogous structure - the septate junctions (SJs). The lack of claudins results in a disruption of SJs integrity leading to a breakdown of the trans-epithelial barrier and to disturbed epithelial morphogenesis. However, little is known about claudin partners for transport mechanisms and membrane organization. Here we present a comprehensive analysis of the claudin proteome in Drosophila by combining biochemical and physiological approaches. Using specific antibodies against the claudin Megatrachea for immunoprecipitation and mass spectrometry we identified 142 proteins associated with Megatrachea in embryos. The Megatrachea interacting proteins were analysed in vivo by tissue-specific knock-down of the corresponding genes using RNA interference. We identified known and novel putative SJs components, such as the gene product of CG3021. Furthermore, our data suggest that the control of secretion processes specific to SJs and dependent on Sec61p may involve Megatrachea interaction with Sec61 subunits. Also, our findings suggest that clathrin-coated vesicles may regulate Megatrachea turnover at the plasma membrane similar to human claudins. As claudins are conserved both in structure and function, our findings offer novel candidate proteins involved in the claudin interactome of vertebrates and invertebrates.
    Journal of Biological Chemistry 08/2012; · 4.65 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The transforming growth factor beta (TGF-beta) family member Decapentaplegic (Dpp) is a key regulator of patterning and growth in Drosophila development. Previous studies have identified a short DNA motif called the silencer element (SE), which recruits a trimeric Smad complex and the repressor Schnurri to downregulate target enhancers upon Dpp signaling. We have now isolated the minimal enhancer of the dad gene and discovered a short motif we termed the activating element (AE). The AE is similar to the SE and recruits the Smad proteins via a conserved mechanism. However, the AE and SE differ at important nucleotide positions. As a consequence, the AE does not recruit Schnurri but rather integrates repressive input by the default repressor Brinker and activating input by the Smad signal transducers Mothers against Dpp (Mad) and Medea via competitive DNA binding. The AE allows the identification of hitherto unknown direct Dpp targets and is functionally conserved in vertebrates.
    Nature Structural & Molecular Biology 12/2009; 17(1):69-76. · 11.90 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The hemoglobin gene 1 (dmeglob1) of the fruit fly Drosophila melanogaster is expressed in the tracheal system and fat body, and has been implicated in hypoxia resistance. Here we investigate the expression levels of dmeglob1 and lactate dehydrogenase (a positive control) in embryos, third instar larvae and adult flies under various regimes of hypoxia and hyperoxia. As expected, mRNA levels of lactate dehydrogenase increased under hypoxia. We show that expression levels of dmeglob1 are decreased under both short- and long-term hypoxia, compared with the normoxic (21% O2) control. By contrast, a hypoxia/reoxygenation regime applied to third instar larvae elevated the level of dmeglob1 mRNA. An excess of O2 (hyperoxia) also triggered an increase in dmeglob1 mRNA. The data suggest that Drosophila hemoglobin may be unlikely to function merely as a myoglobin-like O2 storage protein. Rather, dmeglob1 may protect the fly from an excess of O2, either by buffering the flux of O2 from the tracheoles to the cells or by degrading noxious reactive oxygen species.
    FEBS Journal 10/2008; 275(20):5108-16. · 4.25 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Drosophila provides a powerful experimental system to analyze gene functions in a multi-cellular organism. Here we describe an in vivo method that interferes with the integrity of selected proteins through site-specific cleavage in Drosophila. The technique is based on the highly specific seven-amino-acid recognition site of the tobacco etch virus (TEV) protease. We established transgenic fly lines that direct TEV protease expression in various tissues without affecting fly viability. The insertion of the TEV protease recognition site in defined positions of target proteins mediates their sequence-specific cleavage after controlled TEV protease expression in the fly. Thereby, this technique is a powerful tool that allows the in vivo manipulation of selected proteins in a time- and tissue-specific manner.
    BioTechniques 06/2008; 44(6):765-72. · 2.40 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The Drosophila melanogaster tracheal system and the mammalian lung are branching networks of tubular epithelia that convert during late embryogenesis from liquid- to air-filling. Little is known about how respiratory-tube size and physiology are coordinated. Here, we show that the Drosophila wurst gene encodes a unique J-domain transmembrane protein highly conserved in metazoa. In wurst mutants, respiratory-tube length is increased and lumen clearance is abolished, preventing gas filling of the airways. Wurst is essential for clathrin-mediated endocytosis, which is required for size determination and lumen clearance of the airways. wurst recruits heat shock cognate protein 70-4 and clathrin to the apical membrane of epithelial cells. The sequence conservation of the single Wurst orthologues in mice and humans offer new opportunities for genetic studies of clinically relevant lung syndromes caused by the failure of liquid clearance and respiratory-tube size control.
    Nature Cell Biology 08/2007; 9(7):847-53. · 20.76 Impact Factor
  • Source
    Markus Stahl, Reinhard Schuh, Boris Adryan
    [Show abstract] [Hide abstract]
    ABSTRACT: The embryonic development of the tracheal system of the fruit fly Drosophila provides a paradigm for genetic studies of branching morphogenesis. Efforts of many laboratories have identified Branchless (Bnl, a fibroblast growth factor homologue) and Breathless (Btl, the receptor homologue) as crucial factors at many stages of tracheal system development. The downstream targets of the Bnl/Btl signalling cascade, however, remain mostly unknown. Misexpression of the bnl gene results in specific tracheal phenotypes that lead to larval death. We characterised the transcriptional profiles of targeted over-expression of bnl in the embryonic trachea and of loss-of-function bnl(P1) mutant embryos. Gene expression data was mapped to high-throughput in situ hybridisation based ImaGO-annotation. Thus, we identified and confirmed by quantitative PCR 13 Bnl-dependent genes that are expressed in cells within and outside of the tracheal system.
    Gene Expression Patterns 02/2007; 7(1-2):202-9. · 1.64 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: A key step in organogenesis of the Drosophila tracheal system is the integration of isolated tracheal metameres into a connected tubular network. The interaction of tracheal cells with surrounding mesodermal cells is crucial in this process. In particular, single mesodermal cells called bridge-cells are essential for the guided outgrowth of dorsal trunk branches to direct formation of the main airway, the dorsal trunk. Here, we present evidence that the two leucine-rich repeat transmembrane proteins Capricious and Tartan contribute differently to the formation of branch interconnections during tracheal development. Capricious is specifically localized on the surface of bridge-cells and facilitates the outgrowing dorsal trunk cells of adjacent metameres toward each other. We show that Capricious requires both extracellular and intracellular domains during tracheal branch outgrowth. In contrast, Tartan is expressed broadly in mesodermal cells and exerts its role in tracheal branch outgrowth through its extracellular domain. We propose that Capricious contributes to the instructive role of bridge-cells whereas Tartan provides permissive substrate for the migrating tracheal cells during the network formation.
    Developmental Biology 09/2006; 296(1):253-64. · 3.87 Impact Factor
  • Source
    Boris Adryan, Reinhard Schuh
    [Show abstract] [Hide abstract]
    ABSTRACT: The expected correlation between genetic co-regulation and affiliation to a common biological process is not necessarily the case when numerical cluster algorithms are applied to gene expression data. GO-Cluster uses the tree structure of the Gene Ontology database as a framework for numerical clustering, and thus allowing a simple visualization of gene expression data at various levels of the ontology tree. AVAILABILITY: The 32-bit Windows application is freely available at http://www.mpibpc.mpg.de/go-cluster/
    Bioinformatics 12/2004; 20(16):2851-2. · 5.32 Impact Factor
  • Source
    Matthias Behr, Dietmar Riedel, Reinhard Schuh
    [Show abstract] [Hide abstract]
    ABSTRACT: Vertebrate claudin proteins are integral components of tight junctions, which function as paracellular diffusion barriers in epithelia. We identified Megatrachea (Mega), a Drosophila transmembrane protein homologous to claudins, and show that it acts in septate junctions, the corresponding structure of invertebrates. Our analysis revealed that Mega has transepithelial barrier function similar to the claudins. Also, Mega is necessary for normal tracheal cell morphogenesis but not for apicobasal polarity or epithelial integrity. In addition, we present evidence that Mega is essential for localization of the septate junction protein complex Coracle/Neurexin. The results indicate that claudin-like proteins are functionally conserved between vertebrates and Drosophila.
    Developmental Cell 11/2003; 5(4):611-20. · 12.86 Impact Factor
  • Source
    Christian Wolf, Nina Gerlach, Reinhard Schuh
    [Show abstract] [Hide abstract]
    ABSTRACT: Development of the ectodermally derived Drosophila tracheal system is based on branch outgrowth and fusion that interconnect metamerically arranged tracheal subunits into a highly stereotyped three-dimensional tubular structure. Recent studies have revealed that this process involves a specialized cell type of mesodermal origin, termed bridge-cell. Single bridge-cells are located between adjacent tracheal subunits and serve as guiding posts for the outgrowing dorsal trunk branches. We show that bridge-cell-approaching tracheal cells form filopodia-like cell extensions, which attach to the bridge-cell surface and are essential for the tracheal subunit interconnection. The results of both dominant-negative and gain-of-function experiments suggest that the formation of cell extensions require Cdc42-mediated Drosophila fibroblast growth factor activity.
    EMBO Reports 07/2002; 3(6):563-8. · 7.19 Impact Factor
  • Source
    C Wolf, R Schuh
    [Show abstract] [Hide abstract]
    ABSTRACT: The Drosophila tracheal system, a tubular network, is formed from isolated ectodermal metameres by guided branch outgrowth and branch fusion. Branch outgrowth is triggered by the localized and transient activity of Branchless (Bnl/dFGF). Here, we report the discovery of a mesodermal cell that links the leading cells of outgrowing main branches 2.5 hr before they fuse. This bridge-cell serves as an essential guidance post and needs Hunchback (Hb) activity to exert its function. The bridge-cell provides cues acting in concert with Bnl/dFGF signaling to mediate directed branch outgrowth that ultimately leads to position-specific branch fusion.
    Genes & Development 10/2000; 14(17):2140-5. · 12.44 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We describe a novel Drosophila transcription unit, located in chromosome region 60A. It encodes a zinc finger protein that is expressed in distinct spatial and temporal patterns during embryogenesis. Its initial expression occurs in a stripe at the anterior and the posterior trunk boundary, respectively. The two stripes are activated and spatially controlled by gap-gene activities. The P-element of the enhancer trap line l(2)02970 is inserted in the 5'-region of the transcript and causes a ken and barbie (ken) phenotype, associated with malformation of male genital structures.
    Mechanisms of Development 01/1999; 79(1-2):161-4. · 2.38 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Cell migration during embryonic tracheal system development in Drosophila requires DPP and EGF signaling to generate the archetypal branching pattern. We show that two genes encoding the transcription factors KNIRPS and KNIRPS RELATED possess multiple and redundant functions during tracheal development. knirps/knirps related activity is necessary to mediate DPP signaling which is required for tracheal cell migration and formation of the dorsal and ventral branches. Ectopic knirps or knirps related expression in lateral tracheal cells respecifies their anteroposterior to a dorsoventral migration behavior, similar to that observed in the case of ectopic DPP expression. In dorsal tracheal cells knirps/knirps related activity represses the transcription factor SPALT; this repression is essential for secondary and terminal branch formation. However, in cells of the dorsal trunk, spalt expression is required for normal anteroposterior cell migration and morphogenesis. spalt expression is maintained by the EGF receptor pathway and, hence, some of the opposing activities of the EGF and DPP signaling pathways are mediated by spalt and knirps/knirps related. Furthermore, we provide evidence that the border between cells acquiring dorsal branch and dorsal trunk identity is established by the direct interaction of KNIRPS with a spalt cis-regulatory element.
    Development 01/1999; 125(24):4959-68. · 6.21 Impact Factor
  • Source
    K G Eulenberg, R Schuh
    [Show abstract] [Hide abstract]
    ABSTRACT: The tracheae defective (tdf) gene is required for the formation of the tracheal system during Drosophila embryogenesis. It encodes a putative bZIP transcription factor (TDF). Antibodies directed against TDF detect a nuclear protein in all tracheal cells before invagination and throughout tracheal system morphogenesis. Examination of tdf mutants revealed that tdf activity is not necessary for determining tracheal cell identity but for subsequent morphogenetic cell movements. tdf activity is under the control of trachealess, the key regulator gene for tracheal development. In contrast, tdf activity is not dependent on and does not interfere with the fibroblast growth factor- (FGF) and Decapentaplegic- (DPP) mediated signalling that direct guided tracheal cell migration. Our results suggest that lack of tdf activity affects tracheal cell migration in general rather than specific aspects of cell migration. tdf activity involves a maternal and zygotic component and its requirement is not limited to tracheal system formation. The complex spatiotemporal patterns of TDF expression in the embryo correspond to defects, suggesting that cell migration is impaired. We propose that the bZIP protein TDF functions as a co-regulator of target genes that provide cells with the ability to migrate.
    The EMBO Journal 01/1998; 16(23):7156-65. · 9.82 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The region-specific homeotic gene spalt is involved in the specification of terminal versus trunk structures during early Drosophila embryogenesis. Later in development spalt activity participates in specific processes during organogenesis and larval imaginal disc development. The multiple functions of spalt are reflected in distinct spatio-temporal expression patterns throughout development. Here we show that spalt cis-regulatory sequences for region-specific and organ-specific expression are clustered. Their organization may provide the structural basis for the diversification of expression pattern within the spalt/spalt related/spalt adjacent gene complex. We also examined the transacting factor requirement for the blastodermal spalt expression domains. They are under the genetic control of maternal and gap gene products and we show that these products are able to bind to corresponding spalt cis-acting sequences in vitro. The results suggest that the transacting factors, as defined by genetic studies, functionally interact with the spalt regulatory region. In addition, we provide evidence that a zygotic gene product of the terminal system, Tailless, cooperates with the maternal gene product Caudal and thereby activates gene expression in the terminal region of the embryo.
    Mechanisms of Development 09/1997; 66(1-2):107-18. · 2.38 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We report that DPP signaling is required for directed tracheal cell migration during Drosophila embryogenesis. The failure of tracheal cells to receive the DPP signal from adjacent dorsal and ventral cells results in the absence of dorsal and ventral migrations. Ectopic DPP signaling can reprogram cells in the center of the placode to adopt a dorsoventral migration behavior. The effects observed in response to ectopic DPP signaling are also observed upon the tracheal-specific expression of a constitutive active DPP type I receptor (TKV(Q253D)), indicating that the DPP signal is received and transmitted in tracheal cells to control their migration behavior. DPP signaling determines localized gene expression patterns in the developing tracheal placode, and is also required for the dorsal expression of the recently identified BRANCHLESS (BNL) guidance molecule, the ligand of the BREATHLESS (BTL) receptor. Thus, DPP plays a dual role during tracheal cell migration. It is required to control the dorsal expression of the BNL ligand; in addition, the DPP signal recruits groups of dorsal and ventral tracheal cells and programs them to migrate in dorsal and ventral directions.
    Development 08/1997; 124(14):2741-50. · 6.21 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The region-specific homeotic gene spalt (sal) of Drosophila specifies head and tail as opposed to trunk segments. During later stages of ontogenesis, sal is also expressed and required in a small number of tissues and organs in the developing embryo. sal encodes a zinc finger protein of unusual but characteristic structure. We made use of these unique features to isolate sal-like genes from humans. Here we report the isolation and molecular characterization of two sal-like transcription units, termed Hsal1 and Hsal2, which are located on chromosomes 16q12.1 and 14q11.1-q12.1, respectively. Their transcripts are expressed in a limited number of adult organs, including the brain. While Hsal2 is evenly expressed in different brain areas, Hsal1 transcripts preferentially accumulate in the corpus callosum and the substantia nigra. In the fetal brain, transcripts of both genes were detected in neurons. The arrangement of sal-like zinc finger domains and their high degree of sequence similarity suggest a novel and conserved subfamily of human zinc finger transcription factors that is closely related to the Drosophila gene product encoded by the gene sal.
    Genomics 01/1997; 38(3):291-8. · 3.01 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT:  We report the full coding sequence of a new Drosophila gene, spalt-related, which is homologous and adjacent to the region-specific homeotic gene, spalt. Both genes have three widely spaced sets of C2H2 zinc finger motifs, but spalt-related encodes a fourth pair of C-terminal fingers resembling the Xenopus homologue, Xsal-1. The degrees of sequence divergence among all three members of this family are comparable, suggesting that the Drosophila genes originated from an ancient gene duplication. The spalt-related gene is expressed with quantitative variations from mid-embryogenesis (8–12 h) to the adult stage, but not in ovaries or early embryos. Expression is localized to limited parts of the body, including specific cell populations in the nervous system. In the wing disc, spalt and spalt-related are expressed in indistinguishable domains; in the nervous system and some other organs the expression patterns extensively overlap but are not identical, indicating that the genes have partially diverged in terms of developmental regulation. A characteristic central set of zinc fingers specifically binds to an A/T-rich consensus sequence, defining some DNA binding properties of this ancient family of nuclear factors.
    Development Genes and Evolution 11/1996; 206(5):315-325. · 1.70 Impact Factor

Publication Stats

2k Citations
335.75 Total Impact Points

Institutions

  • 1994–2013
    • Max Planck Institute for Biophysical Chemistry
      • • Department of Molecular Developmental Biology
      • • Group of Molecular Developmental Biology
      Göttingen, Lower Saxony, Germany
  • 1987–2008
    • Max Planck Institute for Developmental Biology
      Tübingen, Baden-Württemberg, Germany
  • 1988
    • Universität Basel
      Bâle, Basel-City, Switzerland