FRINK Linked Data Fragments server

Matches in SemOpenAlex for { <https://semopenalex.org/work/W2023232011> ?p ?o ?g. }

• W2023232011 endingPage "781" @default.
• W2023232011 startingPage "773" @default.
• W2023232011 abstract "Inherited dental malformations constitute a clinically and genetically heterogeneous group of disorders. Here, we report on a severe developmental dental defect that results in a dentin dysplasia phenotype with major microdontia, oligodontia, and shape abnormalities in a highly consanguineous family. Homozygosity mapping revealed a unique zone on 6q27-ter. The two affected children were found to carry a homozygous mutation in SMOC2. Knockdown of smoc2 in zebrafish showed pharyngeal teeth that had abnormalities reminiscent of the human phenotype. Moreover, smoc2 depletion in zebrafish affected the expression of three major odontogenesis genes: dlx2, bmp2, and pitx2. Inherited dental malformations constitute a clinically and genetically heterogeneous group of disorders. Here, we report on a severe developmental dental defect that results in a dentin dysplasia phenotype with major microdontia, oligodontia, and shape abnormalities in a highly consanguineous family. Homozygosity mapping revealed a unique zone on 6q27-ter. The two affected children were found to carry a homozygous mutation in SMOC2. Knockdown of smoc2 in zebrafish showed pharyngeal teeth that had abnormalities reminiscent of the human phenotype. Moreover, smoc2 depletion in zebrafish affected the expression of three major odontogenesis genes: dlx2, bmp2, and pitx2. Dental development is a complex process of reiterative epithelio-mesenchymal interactions between the oral ectoderm and the mesenchymal cells of cephalic neural-crest origin. Tooth development involves numerous genes implied in various signaling pathways such as the Bone Morphogenetic Protein (BMP), Fibroblast Growth Factor (FGF), Sonic hedgehog homolog (SHH), and Wnt pathways.1Fleischmannova J. Matalova E. Tucker A.S. Sharpe P.T. Mouse models of tooth abnormalities.Eur. J. Oral Sci. 2008; 116: 1-10Crossref PubMed Scopus (56) Google Scholar, 2Tummers M. Thesleff I. The importance of signal pathway modulation in all aspects of tooth development.J. Exp. Zoolog. B Mol. Dev. Evol. 2009; 312B: 309-319Crossref PubMed Scopus (182) Google Scholar Tooth developmental abnormalities can affect numbering, shape, size, hard tissue structures (such as enamel or dentin), roots, and periodontium formation, as well as global developmental processes such as dental eruption and resorption. All of these can be affected alone or together in either inherited disorders limited to the orodental sphere or more complex syndromes. Here, we report on a unique and complex tooth malformation phenotype suggestive of autosomal-recessive inheritance in two first-degree cousins born from a highly consanguineous family of Turkish origin. Both children were referred to the Reference Center for Rare Orodental Diseases at the Strasbourg University Hospital because, compared to their healthy siblings, they exhibited extreme microdontia and were missing teeth. Both children presented with extreme microdontia, oligodontia, dental shape anomalies, double permanent-tooth formation, thin enamel, and short roots (with a thin associated alveolar bone), as seen in the spectrum of dentin dysplasia type I (Figure 1).3Barron M.J. McDonnell S.T. Mackie I. Dixon M.J. Hereditary dentine disorders: dentinogenesis imperfecta and dentine dysplasia.Orphanet J. Rare Dis. 2008; 3: 31Crossref PubMed Scopus (122) Google Scholar, 4Ozer L. Karasu H. Aras K. Tokman B. Ersoy E. Dentin dysplasia type I: report of atypical cases in the permanent and mixed dentitions.Oral Surg. Oral Med. Oral Pathol. Oral Radiol. Endod. 2004; 98: 85-90Abstract Full Text Full Text PDF PubMed Scopus (17) Google Scholar The eldest child (III.3) was 10 years old on last examination and presented a well-identified, moderate, X-linked, ichthyosis phenotype known to segregate in the family. The youngest child (III.4), III.3's female cousin, was 5 years old at her first visit and received followed-up examinations for the next 5 years. Both children were born after uneventful pregnancies and were normal at birth. Their developmental milestones are normal to date, and their general physical appearance is unremarkable except for obesity in III.4 (not present in III.3) and very mild bone abnormalities in III.4 (not present in III.3). The orodental findings were documented with the D[4]/phenodent Diagnosing Dental Defects Database. Oligodontia was diagnosed because III.4 was missing 13 permanent teeth and III.3 was missing 14. Anomalies of tooth size were observed, and an extreme microdontia affected both primary teeth (all present) and permanent teeth. However, some permanent teeth were macrodont. Anomalies of tooth shape concerned all existing teeth; extra cusps were visible, and crowns were tiny, globular, and malformed, especially in the primary dentition. Double tooth formation (notched and macrodont) was visible on the permanent incisors. Temporary and permanent molars exhibited taurodontism. Moreover, the molars showed tooth-structure anomalies reminiscent of the dentin dysplasia type I spectrum and had very short roots (Figure 1).3Barron M.J. McDonnell S.T. Mackie I. Dixon M.J. Hereditary dentine disorders: dentinogenesis imperfecta and dentine dysplasia.Orphanet J. Rare Dis. 2008; 3: 31Crossref PubMed Scopus (122) Google Scholar Compared to dentin in the X-ray, the enamel was very thin and had limited contrast. The alveolar bone associated with the primary teeth was hypodeveloped. The primary teeth were mobile and exfoliated prematurely. This study—designed to identify the genetic mutations involved in the dentin dysplasia phenotype—was approved by the ethics committee of the Strasbourg University Hospital. Informed consent was obtained from all individuals who participated in the study. Homozygous mapping via GeneChip Human 250K SNP Affymetrix was performed on affected individuals III.3 and III.4 and nonaffected individuals III.1, III.2, III.5, and III.6. A unique homozygosity region was shared between the two affected individuals and was located between rs2981956 and the end of chromosome 6, defining a 3 Mb region on chromosome 6q27-ter (Figure 2A ). According to Ensembl, this interval contained 69 annotated genes. Genes were selected as likely candidates either because of their known implication in inherited dental conditions or because of their potential dental expression, indicated by the following databases: Helsinki University's Gene Expression in Tooth; the UCSC Genome Browser; the 1000 Genomes Browser; the Ensembl Genome Browser; GeneHub-GEPIS; GenePaint; Eurexpress; and the Zebrafish Information Network (see Web Resources). Two genes were selected with high priority: DACT2 (Dapper antagonist of beta-catenine 2 [OMIM 608966]) and SMOC2 (SPARC-related modular calcium-binding protein [OMIM 607223]). Dact2 modulates Wnt signaling by binding to the intracellular protein Dishevelled (Dvl) and might play an important signal-modulating role in tooth development at the level of the epithelial cells that include the enamel-knot signaling centers and the preameloblasts.5Kettunen P. Kivimäe S. Keshari P. Klein O.D. Cheyette B.N. Luukko K. Dact1-3 mRNAs exhibit distinct expression domains during tooth development.Gene Expr. Patterns. 2010; 10: 140-143Crossref PubMed Scopus (11) Google Scholar The sequencing of DACT2 4 exons was normal in both affected individuals. SMOC2 belongs to a family of matricellular proteins that regulate interactions between cells and the extracellular matrix. The GenePaint database indicated a high level of in situ hybridization in the craniofacial region of the mouse at embryonic day 14.5 (E14.5), especially at the level of the tooth mesenchyme. SMOC2 spans about 226 kb. The coding region of SMOC2 consists of 13 exons. Each domain of SMOC2 is encoded by one or more exons, and the domain borders coincide with splice sites. Sequencing of SMOC2 (ENST00000354536; NM_022138/hg19) revealed a homozygous mutation (c.84+1G>T) in the canonical-splice donor site of intron 1. The parents of both affected children were heterozygous for this mutation, and the children's nonaffected siblings were heterozygous for this mutation (Figure 2B). This mutation was absent in 112 ethnically matched controls. The primer sequences are detailed in Table S1, available online. In order to confirm that SMOC2 was the only gene that carried mutations in the interval, we performed exome sequencing in collaboration with IntegraGen (Evry, France). Exons of patient III.4's DNA were captured via in-solution enrichment methodology (SureSelect Human All Exon Kit v.3, Agilent, Massy, France) with the company's biotinylated oligonucleotide probe library (Agilent Human All Exon 50 Mb Kit v.3). The genomic DNA was then sequenced on a sequencer as paired-end 75 bases (HISEQ, Illumina, San Diego, USA). Image analysis and base calling were performed with Real Time Analysis (RTA) Pipeline version 1.9, set to its default parameters (Illumina). The bioinfomatic analysis of sequencing data was based on the pipeline provided by IntegraGen (Illumina's CASAVA 1.8). CASAVA performs alignment, calls the SNPs on the basis of allele calls and read depth, and detects variants (SNPs and indels). Genetic variation annotation was performed by an in-house pipeline and provided results for the sample in tabulated text files. Among the sequences that could be analyzed, no obvious truncating or nonsense mutation could be identified in any of the 69 genes. We identified 81 substitutions (47 intronic, or in the untranslated regions; 22 synonymous; and 12 missense, of which all were SNPs), seven deletions (all intronic and four SNPs), and one insertion (all intronic and one SNP). However, in our 3 Mb region of interest on chromosome 6, 32 out of 279 baits could not be further analyzed because they did not provide enough coverage. A total of 6.6 kb from the 3 Mb region was not covered sufficiently and overlapped with at least one bait (average bait size was 121 bp) in each of 17 genes (from one to four baits per gene). Thus, taking into account that we had already sequenced two of these genes—SMOC2 and DACT2, which together account for six unread baits—because of their high expected impact on tooth development, 15 genes (out of the 69) that accounted for 5.5 kb were still imperfectly explored and were excluded as interesting candidates in our initial approach. Interestingly, the region that contains our mutation is poorly covered, and we could not identify by whole-exome sequencing the SMOC2 mutation located at the end of exon 1. Moreover, this region of SMOC2 is GC rich, possibly explaining this failure. We compared exome-capture sequencing data from several independent individuals involved in other projects by applying the same setting and confirmed the deficit in the sequence coverage of this specific bait. We would like to point out that although the exome-capture approach is a true revolution in human genetics, it has to be analyzed cautiously; in our case, we would have missed the causative mutation and gene. Although widespread expression of SMOC2 in various human tissues (skin, liver, muscle, lung, spleen, colon, pancreas, kidney) is demonstrated by quantitative reverse transcription PCR (QIAGEN Quantitect primer assay, assay name Hs_SMOC2_1_SG Cat N° QT00085687), we did not succeed in comparing the reverse transcription PCR (RT-PCR) of patients to that of controls because the SMOC2 expression seemed to be very weak in human fibroblasts. SMOC2 was identified by way of an expressed sequence tag database search for proteins homologous to the BM-40 protein family, also known as secreted protein acidic and rich in cysteines (SPARC).6Vannahme C. Gösling S. Paulsson M. Maurer P. Hartmann U. Characterization of SMOC-2, a modular extracellular calcium-binding protein.Biochem. J. 2003; 373: 805-814Crossref PubMed Scopus (83) Google Scholar BM-40 matricellular proteins are extracellular proteins that do not contribute structurally to the extracellular milieu but that regulate interactions between cells and the extracellular matrix.7Lane T.F. Iruela-Arispe M.L. Johnson R.S. Sage E.H. SPARC is a source of copper-binding peptides that stimulate angiogenesis.J. Cell Biol. 1994; 125: 929-943Crossref PubMed Scopus (216) Google Scholar The SPARC/osteonectin/BM-40 family is expressed in many cell types and is highly expressed during embryogenesis, wound healing, and other instances where there is extensive tissue remodelling.8Brekken R.A. Sage E.H. SPARC, a matricellular protein: at the crossroads of cell-matrix communication.Matrix Biol. 2001; 19: 816-827Crossref PubMed Scopus (39) Google Scholar SMOC2 shares an identical domain structure with SMOC1, another secreted modular calcium-binding protein.9Vannahme C. Smyth N. Miosge N. Gösling S. Frie C. Paulsson M. Maurer P. Hartmann U. Characterization of SMOC-1, a novel modular calcium-binding protein in basement membranes.J. Biol. Chem. 2002; 277: 37977-37986Crossref PubMed Scopus (74) Google Scholar In addition to a extracellular calcium-binding (EC) domain homologous to that in BM-40, SMOC1 and SMOC2 share two thyroglobulin-like (TY) domains, an follistatin (FS) domain, and a novel domain. Mutations in SMOC1 have recently been described in patients with a rare recessive developmental disease—Waardenburg anophthalmia syndrome, which mainly involves severe eye malformations and limb defects.10Abouzeid H. Boisset G. Favez T. Youssef M. Marzouk I. Shakankiry N. Bayoumi N. Descombes P. Agosti C. Munier F.L. Schorderet D.F. Mutations in the SPARC-related modular calcium-binding protein 1 gene, SMOC1, cause waardenburg anophthalmia syndrome.Am. J. Hum. Genet. 2011; 88: 92-98Abstract Full Text Full Text PDF PubMed Scopus (48) Google Scholar, 11Okada I. Hamanoue H. Terada K. Tohma T. Megarbane A. Chouery E. Abou-Ghoch J. Jalkh N. Cogulu O. Ozkinay F. et al.SMOC1 is essential for ocular and limb development in humans and mice.Am. J. Hum. Genet. 2011; 88: 30-41Abstract Full Text Full Text PDF PubMed Scopus (74) Google Scholar SMOC2 has been reported as a risk locus for generalized vitiligo in an isolated Romanian community, but this finding has been questioned in another study.12Alkhateeb A. Al-Dain Marzouka N. Qarqaz F. SMOC2 gene variant and the risk of vitiligo in Jordanian Arabs.Eur. J. Dermatol. 2010; 20: 701-704PubMed Google Scholar, 13Birlea S.A. Gowan K. Fain P.R. Spritz R.A. Genome-wide association study of generalized vitiligo in an isolated European founder population identifies SMOC2, in close proximity to IDDM8.J. Invest. Dermatol. 2010; 130: 798-803Crossref PubMed Scopus (57) Google Scholar To date, no inherited condition has been clearly related to SMOC2 mutations. The mutations identified in this family point to a major role of SMOC2 in dental development, and we aimed to gather functional data for such a role. Mouse Smoc2 is located on chromosome 17, and its intron-exon structure is highly conserved in comparison to that of the human gene. Smoc2 is expressed in nearly all adult mouse tissues, and the highest expression is found in the heart, muscles, spleen, and ovaries.6Vannahme C. Gösling S. Paulsson M. Maurer P. Hartmann U. Characterization of SMOC-2, a modular extracellular calcium-binding protein.Biochem. J. 2003; 373: 805-814Crossref PubMed Scopus (83) Google Scholar We next analyzed the expression of Smoc2 during mouse orodental development. We used E14.5 tooth germ cDNAs to perform a study with GeneChip Mouse Gene 1.0 ST arrays (Affymetrix). We detected greater Smoc2 expression in molar than in incisor germs; the opposite pattern was evident for Smoc1 expression. Moreover, in situ hybridization was performed on mouse embryos at E12.5, E14.5, E16.5, and E18.5, which correspond to dental lamina, cap, bell, and bell with differentiated odontoblast and preameloblast stages, respectively. Smoc2 expression was found in the oral ectoderm and the outer dental epithelium at E14.5 and in mesenchymal papilla facing the epithelial loops of molars and the only lingual loop of incisors (Figure S1). To obtain independent functional data on the role of Smoc2 in tooth development, we turned to zebrafish by using the well-established morpholino knockdown technique.14Nasevicius A. Ekker S.C. Effective targeted gene ‘knockdown’ in zebrafish.Nat. Genet. 2000; 26: 216-220Crossref PubMed Scopus (2062) Google Scholar The development and structure of zebrafish teeth reflect the evolutionary, ancestral condition of jawed vertebrates. A distinctive feature of zebrafish dentition is the restriction of teeth to a single pair of pharyngeal bones: Teeth are absent from the oral cavity and are restricted to the fifth ceratobranchials.15Stock D.W. Jackman W.R. Trapani J. Developmental genetic mechanisms of evolutionary tooth loss in cypriniform fishes.Development. 2006; 133: 3127-3137Crossref PubMed Scopus (62) Google Scholar Such dentition is characteristic of the order Cypriniformes.16Jackman W.R. Stock D.W. Transgenic analysis of Dlx regulation in fish tooth development reveals evolutionary retention of enhancer function despite organ loss.Proc. Natl. Acad. Sci. USA. 2006; 103: 19390-19395Crossref PubMed Scopus (41) Google Scholar Morphological signs of tooth initiation appear around the time of hatching (2 days after fertilization) in zebrafish, and the first germs become mineralized and attached to the underlying bone within 4 days after fertilization. Tooth development is similar to that of mammals.17Huysseune A. Van der heyden C. Sire J.Y. Early development of the zebrafish (Danio rerio) pharyngeal dentition (Teleostei, Cyprinidae).Anat. Embryol. (Berl.). 1998; 198: 289-305Crossref PubMed Scopus (85) Google Scholar, 18Van der Heyden C. Huysseune A. Dynamics of tooth formation and replacement in the zebrafish (Danio rerio) (Teleostei, Cyprinidae).Dev. Dyn. 2000; 219: 486-496Crossref PubMed Scopus (83) Google Scholar We therefore used the zebrafish as a model to analyze the function of Smoc2 in tooth development. A search of the zebrafish genome sequence (Ensembl, zv9) revealed a 115 amino acid zebrafish Smoc2 protein (ENSDARP00000108925; named Smoc2a) that shared 68% identity with a 123 amino acid human SMOC2 splice variant (GRCh37, ENSP00000440052). We identified the full-length zebrafish smoc2, which encodes a 429 amino acid protein (Figure S2). The protein shares 67% overall identity with the longest human SMOC2 splice variant (ENSP00000346537). In particular, the C-terminal calcium-binding domains appear to be evolutionarily conserved: Human SMOC2 has numerous splice variants, all of which share the C-terminal region, which includes two calcium-binding domains. In situ hybridization of smoc2a mRNA revealed expression in the pharyngeal pouches and arches. Expression in the area from which the teeth develop was diffuse at 48 hpf (not shown) but condensed by 56 hpf to two bilateral dots, marking the position of the first pair of teeth (Figures S3C–S3D). Morpholinos are an effective way of transiently knocking down zebrafish gene function.14Nasevicius A. Ekker S.C. Effective targeted gene ‘knockdown’ in zebrafish.Nat. Genet. 2000; 26: 216-220Crossref PubMed Scopus (2062) Google Scholar Two morpholinos were created: Mo-smoc2-1 and Mo-smoc2-2. Mo-smoc2-1 was designed to target the smoc2a ATG triplet code to impair the initiation of translation and splicing within larger smoc2 transcripts. Mo-smoc2-2 was designed to target the exon2-intron2 boundary of smoc2a (Figures S2A–S2F). The efficiency of Mo-smoc2-2 was controlled by RT-PCR. The morphant transcript contained both the correctly spliced fragment and a transcript lacking part of the second exon that encodes the calcium-binding domain, leading to a premature stop codon (Figures S2F–S2H). The morpholino appears to activate a cryptic splice site, as previously noted for other morpholinos.19Draper B.W. Morcos P.A. Kimmel C.B. Inhibition of zebrafish fgf8 pre-mRNA splicing with morpholino oligos: a quantifiable method for gene knockdown.Genesis. 2001; 30: 154-156Crossref PubMed Scopus (298) Google Scholar We analyzed the development of the teeth in 5-day-old smoc2-2 morphants by using alizarin red to stain the calcified structures.20Debiais-Thibaud M. Borday-Birraux V. Germon I. Bourrat F. Metcalfe C.J. Casane D. Laurenti P. Development of oral and pharyngeal teeth in the medaka (Oryzias latipes): comparison of morphology and expression of eve1 gene.J. Exp. Zoolog. B Mol. Dev. Evol. 2007; 308: 693-708Crossref PubMed Scopus (34) Google Scholar In both smoc2 morphants, the first two bilateral teeth were smaller than those of the controls (Figure 3, 40 embryos were analyzed). In about 5% of the morphants, the teeth were even undetectable (Figure 3D). The size and presence of the teeth were probably dependent on the level of smoc2 depletion. In addition, although the appearance of the second tooth was already visible in the control embryos, it was undetectable in morphants (Figures 3H–3K). A close inspection of tooth shape revealed a very broad tooth base anchored within the fifth ceratobranchial bone in control larvae (Figures 3H and 3I), whereas it appeared very thin in the morphants (Figures 3J and 3K). In addition, compared to the controls, the smoc2 morphants were missing calcification of some dermal bones and the fifth ceratobranchial bone (Figures 3A–3D), indicating that the skull was affected in morphants. Injections of 0.3 mM of Mo-smoc2-2 and 0.7 mM of Mo-smoc2-1 resulted in a slightly reduced head size in 74% and 56% of the embryos, respectively (category 1, Figure S2D). This reduction was independent of the head volume, excluding the possibility that tooth development could have indirectly been affected by overall impairment of head development (Figures 3B and 3C). To further rule out developmental delay, we analyzed the head musculature in wild-type and smoc2-2 morphants at 5 dpf with a skeletal muscle reporter line (Roostalu, personal communication). All the muscles present in the wild-type were also seen in the morphant, indicating that the development of the head musculature occurred correctly in the morphant (data not shown). In addition, an immunostaining with an antibody against phosphohistone H3 marked proliferating cells. We showed that cell proliferation was not inhibited in the oropharyngeal area of 5 dpf morphants, indicating that the reduced tooth size was not a consequence of an overall reduced proliferation rate (data not shown). Next, we analyzed the developing zebrafish tooth germs by using probes of genes whose orthologs are expressed during mouse odontogenesis. dlx2 is an early marker of the dental epithelium in the mouse.21Thomas B.L. Tucker A.S. Qui M. Ferguson C.A. Hardcastle Z. Rubenstein J.L. Sharpe P.T. Role of Dlx-1 and Dlx-2 genes in patterning of the murine dentition.Development. 1997; 124: 4811-4818Crossref PubMed Google Scholar The zebrafish possesses two semiorthologs (a duplicate gene pair equally related to a single ortholog in another species)22Sharman A.C. Brand M. Evolution and homology of the nervous system: cross-phylum rescues of otd/Otx genes.Trends Genet. 1998; 14: 211-214Abstract Full Text Full Text PDF PubMed Scopus (36) Google Scholar of human DLX2: dlx2a and dlx2b.23Panganiban G. Rubenstein J.L. Developmental functions of the Distal-less/Dlx homeobox genes.Development. 2002; 129: 4371-4386Crossref PubMed Google Scholar, 24Stock D.W. Ellies D.L. Zhao Z. Ekker M. Ruddle F.H. Weiss K.M. The evolution of the vertebrate Dlx gene family.Proc. Natl. Acad. Sci. USA. 1996; 93: 10858-10863Crossref PubMed Scopus (182) Google Scholar Both duplicates are expressed in tooth germs from 48 hr onward.25Thomas B.L. Liu J.K. Rubenstein J.L. Sharpe P.T. Independent regulation of Dlx2 expression in the epithelium and mesenchyme of the first branchial arch.Development. 2000; 127: 217-224PubMed Google Scholar dlx2b is expressed initially in the thickened dental epithelium, but not in the underlying mesenchyme.26Jackman W.R. Draper B.W. Stock D.W. Fgf signaling is required for zebrafish tooth development.Dev. Biol. 2004; 274: 139-157Crossref PubMed Scopus (118) Google Scholar The expression of this gene marks the location of the tooth germ undergoing morphogenesis before mineralization. dlx2b expression in 56 hpf and 72 hpf smoc2 morphants was undetectable in the pharyngeal region where teeth would normally form (Figures 4A–4D ). This absence of expression was observed in 90% of smoc2-1 and smoc2-2 morphants (20 embryos were analyzed for each morpholino, Figures 4B–4D). In contrast, 100% of the control larvae (n > 30) showed normal expression (Figure 4C). Other dlx2 domains, including the forebrain, did not seem to be impaired in the morphants. Because morpholinos can cause cell death in an unspecific manner, we coinjected a morpholino targeting p53 and analyzed dlx2b expression at 72 hpf. Even when apoptosis was blocked, dlx2b expression was gone from the tooth germ area in the morphant (Figures S3I–S3M). In conclusion, apoptosis was not the cause of a lack of dlx2b expression. In contrast to the lack of dlx2b expression, no obvious reduction of expression of the semiortholog dlx2a in smoc2a morphants was revealed through in situ hybridization (Figures S3C and S3D), suggesting that the two orthologs were regulated differently. Bone morphogenetic proteins (BMPs) are known to play multiple roles in tetrapod tooth development and evolution.27Wise S.B. Stock D.W. Conservation and divergence of Bmp2a, Bmp2b, and Bmp4 expression patterns within and between dentitions of teleost fishes.Evol. Dev. 2006; 8: 511-523Crossref PubMed Scopus (43) Google Scholar, 28Wise S.B. Stock D.W. bmp2b and bmp4 are dispensable for zebrafish tooth development.Dev. Dyn. 2010; 239: 2534-2546Crossref PubMed Scopus (21) Google Scholar bmp2a was shown to be expressed in the pharyngeal tooth germ in zebrafish.28Wise S.B. Stock D.W. bmp2b and bmp4 are dispensable for zebrafish tooth development.Dev. Dyn. 2010; 239: 2534-2546Crossref PubMed Scopus (21) Google Scholar In situ hybridization of this transcript revealed a loss of pharyngeal tooth expression of bmp2a in smoc2 morphants (100% for both morpholinos, 20 embryos were analyzed for each) compared to the control embryos (Figures 4E and 4F). In mice, the pituitary homeobox transcription factor PITX2, a DNA- and RNA-binding protein, is expressed in the stomodeal ectoderm from which teeth are eventually derived.29Mucchielli M.L. Mitsiadis T.A. Raffo S. Brunet J.F. Proust J.P. Goridis C. Mouse Otlx2/RIEG expression in the odontogenic epithelium precedes tooth initiation and requires mesenchyme-derived signals for its maintenance.Dev. Biol. 1997; 189: 275-284Crossref PubMed Scopus (128) Google Scholar Zebrafish pitx2 is strongly expressed in bilateral patches in the pharyngeal epithelium.26Jackman W.R. Draper B.W. Stock D.W. Fgf signaling is required for zebrafish tooth development.Dev. Biol. 2004; 274: 139-157Crossref PubMed Scopus (118) Google Scholar Epithelial pitx2 expression in 56 hpf morphants was not as drastically affected as that of dlx2b (Figures 4G–4I). pitx2, which is normally expressed in bilateral patches, showed a reduced expression domain (90% of the smoc2-2 and smoc2-1 morphants, n = 20). In addition, the bilateral patches were often fused (80% of the smoc2-1 morphants, 20 embryos were analyzed for each). This was never observed in the control embryos (20 embryos were analyzed). Other regions of pitx2 expression were unaffected in the morphants. Reduction in the expression of genes considered as tooth germ markers is likely to affect the tooth development itself. Dlx2 has been shown to be involved in the patterning of murine dentition, given that the loss of function of Dlx1 and Dlx2 results in early failure of upper-molar development. Mice null for pitx2 have, among other defects, impaired determination and proliferation of tooth organogenesis.30Lin C.R. Kioussi C. O'Connell S. Briata P. Szeto D. Liu F. Izpisúa-Belmonte J.C. Rosenfeld M.G. Pitx2 regulates lung asymmetry, cardiac positioning and pituitary and tooth morphogenesis.Nature. 1999; 401: 279-282Crossref PubMed Scopus (473) Google Scholar The effect of smoc2 knockdown on dlx2b, bmp2a, and pitx2 expression suggests that smoc2 plays a crucial role in zebrafish dental development upstream of these factors. The fact that, unlike dlx2 expression, smoc2 expression is not initially restricted to the tooth germ suggests that it defines a broader domain from which the tooth germ can develop. Similarly, it was shown that knockout of prdm1a, which is required for posterior arch development, leads to tooth depletion in zebrafish.31Birkholz D.A. Olesnicky Killian E.C. George K.M. Artinger K.B. Prdm1a is necessary for posterior pharyngeal arch development in zebrafish.Dev. Dyn. 2009; 238: 2575-2587Crossref PubMed Scopus (26) Google Scholar Overall, the zebrafish smoc2 analysis suggests that smoc2 has an important function in oropharyngeal development. In light of the highly similar human phenotype—characterized by a very rare dental developmental abnormality—we conclude that Smoc2 plays an evolutionarily conserved role in tooth development. However, the exact role of Smoc2 during development warrants further investigation. Smoc1 and Smoc2 have been shown to be widely expressed in both embryonic and adult mice—Smoc1 mainly in basement membranes of organs and Smoc2 mainly in the extracellular matrix.9Vannahme C. Smyth N. Miosge N. Gösling S. Frie C. Paulsson M. Maurer P. Hartmann U. Characterization of SMOC-1, a novel modular calcium-binding protein in basement membranes.J. Biol. Chem. 2002; 277: 37977-37986Crossref PubMed Scopus (74) Google Scholar, 6Vannahme C. Gösling S. Paulsson M. Maurer P. Hartmann U. Characterization of SMOC-2, a modular extracellular calcium-binding protein.Biochem. J. 2003; 373: 805-814Crossref PubMed Scopus (83) Google Scholar, 32Gersdorff N. Müller M. Schall A. Miosge N. Secreted modular calcium-bind" @default.
• W2023232011 created "2016-06-24" @default.
• W2023232011 creator A5003784655 @default.
• W2023232011 creator A5023845840 @default.
• W2023232011 creator A5025255544 @default.
• W2023232011 creator A5027808272 @default.
• W2023232011 creator A5029706024 @default.
• W2023232011 creator A5037444775 @default.
• W2023232011 creator A5042227654 @default.
• W2023232011 creator A5053585995 @default.
• W2023232011 creator A5054877055 @default.
• W2023232011 creator A5055215537 @default.
• W2023232011 creator A5066070904 @default.
• W2023232011 creator A5070654230 @default.
• W2023232011 creator A5078931117 @default.
• W2023232011 date "2011-12-01" @default.
• W2023232011 modified "2023-10-13" @default.
• W2023232011 title "Homozygosity Mapping and Candidate Prioritization Identify Mutations, Missed by Whole-Exome Sequencing, in SMOC2, Causing Major Dental Developmental Defects" @default.
• W2023232011 cites W1674167019 @default.
• W2023232011 cites W1838552284 @default.
• W2023232011 cites W1941527389 @default.
• W2023232011 cites W1965900783 @default.
• W2023232011 cites W1971964553 @default.
• W2023232011 cites W1979081269 @default.
• W2023232011 cites W1981898286 @default.
• W2023232011 cites W1982066003 @default.
• W2023232011 cites W1986071377 @default.
• W2023232011 cites W1988173433 @default.
• W2023232011 cites W1993715760 @default.
• W2023232011 cites W1994905815 @default.
• W2023232011 cites W1997912181 @default.
• W2023232011 cites W1998756807 @default.
• W2023232011 cites W2016671423 @default.
• W2023232011 cites W2019634239 @default.
• W2023232011 cites W2020749395 @default.
• W2023232011 cites W2024479227 @default.
• W2023232011 cites W2035348850 @default.
• W2023232011 cites W2038499023 @default.
• W2023232011 cites W2045214716 @default.
• W2023232011 cites W2049132020 @default.
• W2023232011 cites W2052374677 @default.
• W2023232011 cites W2070801267 @default.
• W2023232011 cites W2071014852 @default.
• W2023232011 cites W2080730190 @default.
• W2023232011 cites W2083642753 @default.
• W2023232011 cites W2084363118 @default.
• W2023232011 cites W2087752979 @default.
• W2023232011 cites W2088356281 @default.
• W2023232011 cites W2095724936 @default.
• W2023232011 cites W2108569257 @default.
• W2023232011 cites W2140146453 @default.
• W2023232011 cites W2151567718 @default.
• W2023232011 cites W2153639555 @default.
• W2023232011 cites W2184681883 @default.
• W2023232011 doi "https://doi.org/10.1016/j.ajhg.2011.11.002" @default.
• W2023232011 hasPubMedCentralId "https://www.ncbi.nlm.nih.gov/pmc/articles/3234372" @default.
• W2023232011 hasPubMedId "https://pubmed.ncbi.nlm.nih.gov/22152679" @default.
• W2023232011 hasPublicationYear "2011" @default.
• W2023232011 type Work @default.
• W2023232011 sameAs 2023232011 @default.
• W2023232011 citedByCount "88" @default.
• W2023232011 countsByYear W20232320112012 @default.
• W2023232011 countsByYear W20232320112013 @default.
• W2023232011 countsByYear W20232320112014 @default.
• W2023232011 countsByYear W20232320112015 @default.
• W2023232011 countsByYear W20232320112016 @default.
• W2023232011 countsByYear W20232320112017 @default.
• W2023232011 countsByYear W20232320112018 @default.
• W2023232011 countsByYear W20232320112019 @default.
• W2023232011 countsByYear W20232320112020 @default.
• W2023232011 countsByYear W20232320112021 @default.
• W2023232011 countsByYear W20232320112022 @default.
• W2023232011 countsByYear W20232320112023 @default.
• W2023232011 crossrefType "journal-article" @default.
• W2023232011 hasAuthorship W2023232011A5003784655 @default.
• W2023232011 hasAuthorship W2023232011A5023845840 @default.
• W2023232011 hasAuthorship W2023232011A5025255544 @default.
• W2023232011 hasAuthorship W2023232011A5027808272 @default.
• W2023232011 hasAuthorship W2023232011A5029706024 @default.
• W2023232011 hasAuthorship W2023232011A5037444775 @default.
• W2023232011 hasAuthorship W2023232011A5042227654 @default.
• W2023232011 hasAuthorship W2023232011A5053585995 @default.
• W2023232011 hasAuthorship W2023232011A5054877055 @default.
• W2023232011 hasAuthorship W2023232011A5055215537 @default.
• W2023232011 hasAuthorship W2023232011A5066070904 @default.
• W2023232011 hasAuthorship W2023232011A5070654230 @default.
• W2023232011 hasAuthorship W2023232011A5078931117 @default.
• W2023232011 hasBestOaLocation W20232320111 @default.
• W2023232011 hasConcept C104317684 @default.
• W2023232011 hasConcept C10590036 @default.
• W2023232011 hasConcept C130895681 @default.
• W2023232011 hasConcept C162324750 @default.
• W2023232011 hasConcept C16671776 @default.
• W2023232011 hasConcept C2777615720 @default.
• W2023232011 hasConcept C501734568 @default.
• W2023232011 hasConcept C539667460 @default.
• W2023232011 hasConcept C54355233 @default.
• W2023232011 hasConcept C70721500 @default.

• next