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Alibardi L. Immunolocalization of lix1 in the regenerating tail of lizard indicates that the protein is mainly present in the nervous tissue. Acta Histochem 2023; 125:152113. [PMID: 37948784 DOI: 10.1016/j.acthis.2023.152113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 11/02/2023] [Accepted: 11/03/2023] [Indexed: 11/12/2023]
Abstract
PURPOSE Lizard regeneration derives from the re-activation of a number of developmental genes after tail amputation. Among genes with the highest expression, as indicated from the transcriptome, is lix1 which functional role is not known. METHOD An antibody that cross-reacts with the lizard Podarcis muralis lix1 has been utilized to detect by immunofluorescence the sites of localization of the protein in the regenerating tail. RESULTS Lix1-protein is almost exclusively localized in the regenerating spinal cord (ependyma) and nerves growing into the blastema, in sparse blastema cells but is undetectable in other tissues. CONCLUSIONS Since the spinal cord is essential to stimulate tail regeneration it is hypothesized that the lix1 protein is part of the signaling or growing factors produced from the regenerating spinal cord that are needed for tail regeneration of the lizard tail.
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Affiliation(s)
- Lorenzo Alibardi
- Comparative Histolab Padova and Department of Biology of the University of Bologna, Italy.
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2
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Farkas K, Ferretti E. Derivation of Human Extraembryonic Mesoderm-like Cells from Primitive Endoderm. Int J Mol Sci 2023; 24:11366. [PMID: 37511125 PMCID: PMC10380231 DOI: 10.3390/ijms241411366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 06/22/2023] [Accepted: 06/29/2023] [Indexed: 07/30/2023] Open
Abstract
In vitro modeling of human peri-gastrulation development is a valuable tool for understanding embryogenetic mechanisms. The extraembryonic mesoderm (ExM) is crucial in supporting embryonic development by forming tissues such as the yolk sac, allantois, and chorionic villi. However, the origin of human ExM remains only partially understood. While evidence suggests a primitive endoderm (PrE) origin based on morphological findings, current in vitro models use epiblast-like cells. To address this gap, we developed a protocol to generate ExM-like cells from PrE-like cell line called naïve extraembryonic endoderm (nEnd). We identified the ExM-like cells by specific markers (LUM and ANXA1). Moreover, these in vitro-produced ExM cells displayed angiogenic potential on a soft matrix, mirroring their physiological role in vasculogenesis. By integrating single-cell RNA sequencing (scRNAseq) data, we found that the ExM-like cells clustered with the LUM/ANXA1-rich cell populations of the gastrulating embryo, indicating similarity between in vitro and ex utero cell populations. This study confirms the derivation of ExM from PrE and establishes a cell culture system that can be utilized to investigate ExM during human peri-gastrulation development, both in monolayer cultures and more complex models.
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Affiliation(s)
- Karin Farkas
- Novo Nordisk Foundation Center for Stem Cell Biology (DanStem), University of Copenhagen, 1165 Copenhagen, Denmark
- Department of Biomedical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Elisabetta Ferretti
- Novo Nordisk Foundation Center for Stem Cell Biology (DanStem), University of Copenhagen, 1165 Copenhagen, Denmark
- Department of Cellular and Molecular Medicine, University of Copenhagen, 2200 Copenhagen, Denmark
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Guérin A, Angebault C, Kinet S, Cazevieille C, Rojo M, Fauconnier J, Lacampagne A, Mourier A, Taylor N, de Santa Barbara P, Faure S. LIX1-mediated changes in mitochondrial metabolism control the fate of digestive mesenchyme-derived cells. Redox Biol 2022; 56:102431. [PMID: 35988446 PMCID: PMC9420520 DOI: 10.1016/j.redox.2022.102431] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 08/03/2022] [Indexed: 11/06/2022] Open
Abstract
YAP1 and TAZ are transcriptional co-activator proteins that play fundamental roles in many biological processes, from cell proliferation and cell lineage fate determination to tumorigenesis. We previously demonstrated that Limb Expression 1 (LIX1) regulates YAP1 and TAZ activity and controls digestive mesenchymal progenitor proliferation. However, LIX1 mode of action remains elusive. Here, we found that endogenous LIX1 is localized in mitochondria and is anchored to the outer mitochondrial membrane through S-palmitoylation of cysteine 84, a residue conserved in all LIX1 orthologs. LIX1 downregulation altered the mitochondrial ultrastructure, resulting in a significantly decreased respiration and attenuated production of mitochondrial reactive oxygen species (mtROS). Mechanistically, LIX1 knock-down impaired the stability of the mitochondrial proteins PHB2 and OPA1 that are found in complexes with mitochondrial-specific phospholipids and are required for cristae organization. Supplementation with unsaturated fatty acids counteracted the effects of LIX1 knock-down on mitochondrial morphology and ultrastructure and restored YAP1/TAZ signaling. Collectively, our data demonstrate that LIX1 is a key regulator of cristae organization, modulating mtROS level and subsequently regulating the signaling cascades that control fate commitment of digestive mesenchyme-derived cells. LIX1 is tightly anchored to the outer membrane of mitochondria. LIX1 mitochondrial localization is mediated by S-palmitoylation on cysteine 84. LIX1 knock-down reduces the stability of the mitochondrial proteins PHB2 and OPA1 and impairs cristae organization. Redox signaling modulations regulate YAP1/TAZ activity and control fate commitment of digestive mesenchyme-derived cells.
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Affiliation(s)
- Amandine Guérin
- PhyMedExp, University of Montpellier, INSERM, CNRS, Montpellier, France
| | - Claire Angebault
- PhyMedExp, University of Montpellier, INSERM, CNRS, Montpellier, France
| | - Sandrina Kinet
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, Montpellier, France
| | - Chantal Cazevieille
- Institut de Neurosciences de Montpellier, University of Montpellier, INSERM, Montpellier, France
| | - Manuel Rojo
- Centre National de la Recherche Scientifique, Université de Bordeaux, IBGC UMR, 5095, Bordeaux, France
| | - Jérémy Fauconnier
- PhyMedExp, University of Montpellier, INSERM, CNRS, Montpellier, France
| | - Alain Lacampagne
- PhyMedExp, University of Montpellier, INSERM, CNRS, Montpellier, France
| | - Arnaud Mourier
- Centre National de la Recherche Scientifique, Université de Bordeaux, IBGC UMR, 5095, Bordeaux, France
| | - Naomi Taylor
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, Montpellier, France
| | | | - Sandrine Faure
- PhyMedExp, University of Montpellier, INSERM, CNRS, Montpellier, France.
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Vitulo N, Dalla Valle L, Skobo T, Valle G, Alibardi L. Transcriptome analysis of the regenerating tail vs. the scarring limb in lizard reveals pathways leading to successful vs. unsuccessful organ regeneration in amniotes. Dev Dyn 2017; 246:116-134. [DOI: 10.1002/dvdy.24474] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 11/12/2016] [Accepted: 11/16/2016] [Indexed: 12/29/2022] Open
Affiliation(s)
- Nicola Vitulo
- Department of Biotechnology; University of Verona; Italy
| | | | - Tatjana Skobo
- Department of Biology; University of Padova; Padova Italy
| | - Giorgio Valle
- Department of Biology; University of Padova; Padova Italy
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5
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McKey J, Martire D, de Santa Barbara P, Faure S. LIX1 regulates YAP1 activity and controls the proliferation and differentiation of stomach mesenchymal progenitors. BMC Biol 2016; 14:34. [PMID: 27125505 PMCID: PMC4848777 DOI: 10.1186/s12915-016-0257-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Accepted: 04/18/2016] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Smooth muscle cell (SMC) plasticity maintains the balance between differentiated SMCs and proliferative mesenchymal progenitors, crucial for muscular tissue homeostasis. Studies on the development of mesenchymal progenitors into SMCs have proven useful in identifying molecular mechanisms involved in digestive musculature plasticity in physiological and pathological conditions. RESULTS Here, we show that Limb Expression 1 (LIX1) molecularly defines the population of mesenchymal progenitors in the developing stomach. Using in vivo functional approaches in the chick embryo, we demonstrate that LIX1 is a key regulator of stomach SMC development. We show that LIX1 is required for stomach SMC determination to regulate the expression of the pro-proliferative gene YAP1 and mesenchymal cell proliferation. However, as stomach development proceeds, sustained LIX1 expression has a negative impact on further SMC differentiation and this is associated with a decrease in YAP1 activity. CONCLUSIONS We demonstrate that expression of LIX1 must be tightly regulated to allow fine-tuning of the transcript levels and state of activation of the pro-proliferative transcriptional coactivator YAP1 to regulate proliferation rates of stomach mesenchymal progenitors and their differentiation. Our data highlight dual roles for LIX1 and YAP1 and provide new insights into the regulation of cell density-dependent proliferation, which is essential for the development and homeostasis of organs.
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Affiliation(s)
- Jennifer McKey
- PhyMedExp, INSERM U1046, CNRS UMR 9214, University of Montpellier, 34295, Montpellier, France
| | - Delphine Martire
- PhyMedExp, INSERM U1046, CNRS UMR 9214, University of Montpellier, 34295, Montpellier, France
| | - Pascal de Santa Barbara
- PhyMedExp, INSERM U1046, CNRS UMR 9214, University of Montpellier, 34295, Montpellier, France
| | - Sandrine Faure
- PhyMedExp, INSERM U1046, CNRS UMR 9214, University of Montpellier, 34295, Montpellier, France.
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6
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Tassano E, Gimelli S, Divizia MT, Lerone M, Vaccari C, Puliti A, Gimelli G. Thrombocytopenia-absent radius (TAR) syndrome due to compound inheritance for a 1q21.1 microdeletion and a low-frequency noncoding RBM8A SNP: a new familial case. Mol Cytogenet 2015; 8:87. [PMID: 26550033 PMCID: PMC4635577 DOI: 10.1186/s13039-015-0188-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 10/27/2015] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Thrombocytopenia-absent radius syndrome (TAR; MIM 274000) is a rare autosomal recessive disorder combining specific skeletal abnormalities with a reduced platelet count. TAR syndrome has been associated with the compound inheritance of an interstitial microdeletion in 1q21.1 and a low frequency noncoding RBM8A SNP. RESULTS Here, we report on a patient with scapulo-humeral hypoplasia, bilateral radio-ulnar agenesis with intact thumbs, bilateral proximal positioning of the first metacarpal, bilateral fifth finger clinodactyly, bilateral radial deviation of the hands, and thrombocytopenia. Molecular studies showed compound heterozygosity for the 1q21.1 microdeletion and the RBM8A rs139428292 variant in hemizygous state, inherited from the father and the mother, respectively. A second aborted fetus presented TAR features and 1q21.1 microdeletion. DISCUSSION The complex inheritance pattern resulted in reduced expression of Y14, the protein encoded by RBM8A, and a component of the core exon-junction complex (EJC) in platelets. Further studies are needed to explain how Y14 insufficiency and subsequent defects of the EJC could cause the skeletal, haematological and additional features of TAR syndrome. In this study, we discuss other factors that could influence the overall phenotype of patients affected by TAR syndrome. CONCLUSION In this study, we discuss other factors that could influence the overall phenotype of patients affected by TAR syndrome.
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Affiliation(s)
- Elisa Tassano
- />Laboratorio di Citogentica, Istituto Giannina Gaslini, L.go G.Gaslini 5, 16147 Genoa, Italy
| | - Stefania Gimelli
- />Service of Genetic Medicine, University Hospitals of Geneva, 1211 Geneva, Switzerland
| | | | - Margherita Lerone
- />U.O.C. Medical Genetics, Istituto Giannina Gaslini, 16147 Genoa, Italy
| | | | - Aldamaria Puliti
- />U.O.C. Medical Genetics, Istituto Giannina Gaslini, 16147 Genoa, Italy
- />DiNOGMI, University of Genoa, 16147 Genoa, Italy
| | - Giorgio Gimelli
- />Laboratorio di Citogentica, Istituto Giannina Gaslini, L.go G.Gaslini 5, 16147 Genoa, Italy
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Nakamura S, Kahyo T, Tao H, Shibata K, Kurabe N, Yamada H, Shinmura K, Ohnishi K, Sugimura H. Novel roles for LIX1L in promoting cancer cell proliferation through ROS1-mediated LIX1L phosphorylation. Sci Rep 2015; 5:13474. [PMID: 26310847 PMCID: PMC4550850 DOI: 10.1038/srep13474] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Accepted: 07/27/2015] [Indexed: 11/25/2022] Open
Abstract
Herein, we report the characterization of Limb expression 1-like, (LIX1L), a putative RNA-binding protein (RBP) containing a double-stranded RNA binding motif, which is highly expressed in various cancer tissues. Analysis of MALDI-TOF/TOF mass spectrometry and RNA immunoprecipitation-sequencing of interacting proteins and the microRNAs (miRNAs) bound to LIX1L revealed that LIX1L interacts with proteins (RIOK1, nucleolin and PABPC4) and miRNAs (has-miRNA-520a-5p, −300, −216b, −326, −190a, −548b-3p, −7–5p and −1296) in HEK-293 cells. Moreover, the reduction of phosphorylated Tyr136 (pTyr136) in LIX1L through the homeodomain peptide, PY136, inhibited LIX1L-induced cell proliferation in vitro, and PY136 inhibited MKN45 cell proliferation in vivo. We also determined the miRNA-targeted genes and showed that was apoptosis induced through the reduction of pTyr136. Moreover, ROS1, HCK, ABL1, ABL2, JAK3, LCK and TYR03 were identified as candidate kinases responsible for the phosphorylation of Tyr136 of LIX1L. These data provide novel insights into the biological significance of LIX1L, suggesting that this protein might be an RBP, with implications for therapeutic approaches for targeting LIX1L in LIX1L-expressing cancer cells.
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Affiliation(s)
- Satoki Nakamura
- Department of Tumor Pathology, 1-20-1 Handayama, Higashi-ku, Hamamatsu, Shizuoka 431-3192, Japan
| | - Tomoaki Kahyo
- Department of Tumor Pathology, 1-20-1 Handayama, Higashi-ku, Hamamatsu, Shizuoka 431-3192, Japan
| | - Hong Tao
- Department of Tumor Pathology, 1-20-1 Handayama, Higashi-ku, Hamamatsu, Shizuoka 431-3192, Japan
| | - Kiyoshi Shibata
- Equipment Center, 1-20-1 Handayama, Higashi-ku, Hamamatsu, Shizuoka 431-3192, Japan
| | - Nobuya Kurabe
- Department of Tumor Pathology, 1-20-1 Handayama, Higashi-ku, Hamamatsu, Shizuoka 431-3192, Japan
| | - Hidetaka Yamada
- Department of Tumor Pathology, 1-20-1 Handayama, Higashi-ku, Hamamatsu, Shizuoka 431-3192, Japan
| | - Kazuya Shinmura
- Department of Tumor Pathology, 1-20-1 Handayama, Higashi-ku, Hamamatsu, Shizuoka 431-3192, Japan
| | - Kazunori Ohnishi
- Cancer Center, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu, Shizuoka 431-3192, Japan
| | - Haruhiko Sugimura
- Department of Tumor Pathology, 1-20-1 Handayama, Higashi-ku, Hamamatsu, Shizuoka 431-3192, Japan
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8
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Kumar V, Kutschera VE, Nilsson MA, Janke A. Genetic signatures of adaptation revealed from transcriptome sequencing of Arctic and red foxes. BMC Genomics 2015; 16:585. [PMID: 26250829 PMCID: PMC4528681 DOI: 10.1186/s12864-015-1724-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 06/26/2015] [Indexed: 11/17/2022] Open
Abstract
Background The genus Vulpes (true foxes) comprises numerous species that inhabit a wide range of habitats and climatic conditions, including one species, the Arctic fox (Vulpes lagopus) which is adapted to the arctic region. A close relative to the Arctic fox, the red fox (Vulpes vulpes), occurs in subarctic to subtropical habitats. To study the genetic basis of their adaptations to different environments, transcriptome sequences from two Arctic foxes and one red fox individual were generated and analyzed for signatures of positive selection. In addition, the data allowed for a phylogenetic analysis and divergence time estimate between the two fox species. Results The de novo assembly of reads resulted in more than 160,000 contigs/transcripts per individual. Approximately 17,000 homologous genes were identified using human and the non-redundant databases. Positive selection analyses revealed several genes involved in various metabolic and molecular processes such as energy metabolism, cardiac gene regulation, apoptosis and blood coagulation to be under positive selection in foxes. Branch site tests identified four genes to be under positive selection in the Arctic fox transcriptome, two of which are fat metabolism genes. In the red fox transcriptome eight genes are under positive selection, including molecular process genes, notably genes involved in ATP metabolism. Analysis of the three transcriptomes and five Sanger re-sequenced genes in additional individuals identified a lower genetic variability within Arctic foxes compared to red foxes, which is consistent with distribution range differences and demographic responses to past climatic fluctuations. A phylogenomic analysis estimated that the Arctic and red fox lineages diverged about three million years ago. Conclusions Transcriptome data are an economic way to generate genomic resources for evolutionary studies. Despite not representing an entire genome, this transcriptome analysis identified numerous genes that are relevant to arctic adaptation in foxes. Similar to polar bears, fat metabolism seems to play a central role in adaptation of Arctic foxes to the cold climate, as has been identified in the polar bear, another arctic specialist. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-1724-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Vikas Kumar
- Senckenberg Biodiversity and Climate Research Center, Senckenberg Gesellschaft für Naturforschung, Senckenberganlage 25, D-60325, Frankfurt am Main, Germany.
| | - Verena E Kutschera
- Senckenberg Biodiversity and Climate Research Center, Senckenberg Gesellschaft für Naturforschung, Senckenberganlage 25, D-60325, Frankfurt am Main, Germany. .,Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18D, SE-75236, Uppsala, Sweden.
| | - Maria A Nilsson
- Senckenberg Biodiversity and Climate Research Center, Senckenberg Gesellschaft für Naturforschung, Senckenberganlage 25, D-60325, Frankfurt am Main, Germany.
| | - Axel Janke
- Senckenberg Biodiversity and Climate Research Center, Senckenberg Gesellschaft für Naturforschung, Senckenberganlage 25, D-60325, Frankfurt am Main, Germany. .,Evolution & Diversity, Goethe University Frankfurt, Institute for Ecology, Biologicum, Max-von-Laue-Str.13, D-60439, Frankfurt am Main, Germany.
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9
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Deak KL, Horn SR, Rehder CW. The evolving picture of microdeletion/microduplication syndromes in the age of microarray analysis: variable expressivity and genomic complexity. Clin Lab Med 2011; 31:543-64, viii. [PMID: 22118736 DOI: 10.1016/j.cll.2011.08.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Several new microdeletion and microduplication syndromes have been discovered in a genotype-first approach. Many of these disorders are caused by nonallelic homologous recombination between blocks of segmental duplication. The authors describe 9 regions for which copy number alteration is proposed to cause an abnormal phenotype. Some of these disorders have been observed in affected individuals and individuals lacking a clearly abnormal phenotype. These deletions and duplications are thought to be contributory, but not always sufficient, to elicit an abnormal outcome. Additional studies are necessary to further evaluate the penetrance and delineate the clinical spectrum associated with many of these newly described disorders.
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Affiliation(s)
- Kristen L Deak
- Department of Pathology, Duke University, Durham, NC, USA
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10
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Bando T, Hamada Y, Kurita K, Nakamura T, Mito T, Ohuchi H, Noji S. Lowfat, a mammalian Lix1 homologue, regulates leg size and growth under the Dachsous/Fat signaling pathway during tissue regeneration†. Dev Dyn 2011; 240:1440-53. [DOI: 10.1002/dvdy.22647] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/01/2011] [Indexed: 01/15/2023] Open
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11
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Mao Y, Kucuk B, Irvine KD. Drosophila lowfat, a novel modulator of Fat signaling. Development 2009; 136:3223-33. [PMID: 19710173 DOI: 10.1242/dev.036152] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The Fat-Hippo-Warts signaling network regulates both transcription and planar cell polarity. Despite its crucial importance to the normal control of growth and planar polarity, we have only a limited understanding of the mechanisms that regulate Fat. We report here the identification of a conserved cytoplasmic protein, Lowfat (Lft), as a modulator of Fat signaling. Drosophila Lft, and its human homologs LIX1 and LIX1-like, bind to the cytoplasmic domains of the Fat ligand Dachsous, the receptor protein Fat, and its human homolog FAT4. Lft protein can localize to the sub-apical membrane in disc cells, and this membrane localization is influenced by Fat and Dachsous. Lft expression is normally upregulated along the dorsoventral boundary of the developing wing, and is responsible for elevated levels of Fat protein there. Levels of Fat and Dachsous protein are reduced in lft mutant cells, and can be increased by overexpression of Lft. lft mutant animals exhibit a wing phenotype similar to that of animals with weak alleles of fat, and lft interacts genetically with both fat and dachsous. These studies identify Lft as a novel component of the Fat signaling pathway, and the Lft-mediated elevation of Fat levels as a mechanism for modulating Fat signaling.
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Affiliation(s)
- Yaopan Mao
- Howard Hughes Medical Institute, Waksman Institute and Department of Molecular Biology and Biochemistry, Rutgers The State University of New Jersey, Piscataway, NJ 08854, USA
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12
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Klopocki E, Schulze H, Strauss G, Ott CE, Hall J, Trotier F, Fleischhauer S, Greenhalgh L, Newbury-Ecob RA, Neumann LM, Habenicht R, König R, Seemanova E, Megarbane A, Ropers HH, Ullmann R, Horn D, Mundlos S. Complex inheritance pattern resembling autosomal recessive inheritance involving a microdeletion in thrombocytopenia-absent radius syndrome. Am J Hum Genet 2007; 80:232-40. [PMID: 17236129 PMCID: PMC1785342 DOI: 10.1086/510919] [Citation(s) in RCA: 251] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2006] [Accepted: 11/14/2006] [Indexed: 11/03/2022] Open
Abstract
Thrombocytopenia-absent radius (TAR) syndrome is characterized by hypomegakaryocytic thrombocytopenia and bilateral radial aplasia in the presence of both thumbs. Other frequent associations are congenital heart disease and a high incidence of cow's milk intolerance. Evidence for autosomal recessive inheritance comes from families with several affected individuals born to unaffected parents, but several other observations argue for a more complex pattern of inheritance. In this study, we describe a common interstitial microdeletion of 200 kb on chromosome 1q21.1 in all 30 investigated patients with TAR syndrome, detected by microarray-based comparative genomic hybridization. Analysis of the parents revealed that this deletion occurred de novo in 25% of affected individuals. Intriguingly, inheritance of the deletion along the maternal line as well as the paternal line was observed. The absence of this deletion in a cohort of control individuals argues for a specific role played by the microdeletion in the pathogenesis of TAR syndrome. We hypothesize that TAR syndrome is associated with a deletion on chromosome 1q21.1 but that the phenotype develops only in the presence of an additional as-yet-unknown modifier (mTAR).
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Affiliation(s)
- Eva Klopocki
- Institut für Medizinische Genetik, Charité Universitätsmedizin Berlin, Berlin, Germany
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13
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Fyfe JC, Menotti-Raymond M, David VA, Brichta L, Schäffer AA, Agarwala R, Murphy WJ, Wedemeyer WJ, Gregory BL, Buzzell BG, Drummond MC, Wirth B, O'Brien SJ. An approximately 140-kb deletion associated with feline spinal muscular atrophy implies an essential LIX1 function for motor neuron survival. Genome Res 2006; 16:1084-90. [PMID: 16899656 PMCID: PMC1557767 DOI: 10.1101/gr.5268806] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The leading genetic cause of infant mortality is spinal muscular atrophy (SMA), a clinically and genetically heterogeneous group of disorders. Previously we described a domestic cat model of autosomal recessive, juvenile-onset SMA similar to human SMA type III. Here we report results of a whole-genome scan for linkage in the feline SMA pedigree using recently developed species-specific and comparative mapping resources. We identified a novel SMA gene candidate, LIX1, in an approximately140-kb deletion on feline chromosome A1q in a region of conserved synteny to human chromosome 5q15. Though LIX1 function is unknown, the predicted secondary structure is compatible with a role in RNA metabolism. LIX1 expression is largely restricted to the central nervous system, primarily in spinal motor neurons, thus offering explanation of the tissue restriction of pathology in feline SMA. An exon sequence screen of 25 human SMA cases, not otherwise explicable by mutations at the SMN1 locus, failed to identify comparable LIX1 mutations. Nonetheless, a LIX1-associated etiology in feline SMA implicates a previously undetected mechanism of motor neuron maintenance and mandates consideration of LIX1 as a candidate gene in human SMA when SMN1 mutations are not found.
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Affiliation(s)
- John C Fyfe
- Laboratory of Comparative Medical Genetics, Department of Microbiology & Molecular Genetics, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan 48824, USA.
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14
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Moeller C, Swindell EC, Kispert A, Eichele G. Carboxypeptidase Z (CPZ) modulates Wnt signaling and regulates the development of skeletal elements in the chicken. Development 2003; 130:5103-11. [PMID: 12944424 DOI: 10.1242/dev.00686] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Carboxypeptidase Z (CPZ) is a secreted Zn-dependent enzyme whose biological function is largely unknown. CPZ has a bipartite structure consisting of an N-terminal cysteine-rich domain (CRD) and a C-terminal catalytic domain. In the early chicken embryo CPZ is initially expressed throughout the somites and subsequently becomes restricted to the sclerotome. To initiate a functional analysis of CPZ, a CPZ producing retroviral vector was applied to the presomitic mesoderm at the level of the future wing. This resulted in a loss of the scapular blade and of rostral ribs. Such dysmorphogenesis is preceded by ectopic Pax3 expression in the hypaxial part of the dermomyotome, a region from which the blade of the scapula normally derives. A mutant CPZ, lacking a critical active site glutamate, fails to induce Pax3 expression and does not cause skeletal defects. The induction of Pax3, a Wnt-responsive gene in somites, and the presence of a CRD prompted us to examine whether CPZ affects Wnt signaling. In an in vitro assay we found that CPZ, but not its inactive mutant form, enhances the Wnt-dependent induction of the homeobox gene Cdx1. In addition, immunoprecipitation experiments suggest that the CRD of CPZ acts as a binding domain for Wnt. Taken together these data provide the first evidence for CPZ playing a role in Wnt signaling.
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Affiliation(s)
- Carsten Moeller
- Max Planck Institute of Experimental Endocrinology, Hannover, Germany 30625
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