Talk:Developmental Signals - Tbx
|About Discussion Pages|
Cite this page: Hill, M.A. (2020, November 30) Embryology Developmental Signals - Tbx. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Talk:Developmental_Signals_-_Tbx
Karolak JA, Vincent M, Deutsch G, Gambin T, Cogné B, Pichon O, Vetrini F, Mefford HC, Dines JN, Golden-Grant K, Dipple K, Freed AS, Leppig KA, Dishop M, Mowat D, Bennetts B, Gifford AJ, Weber MA, Lee AF, Boerkoel CF, Bartell TM, Ward-Melver C, Besnard T, Petit F, Bache I, Tümer Z, Denis-Musquer M, Joubert M, Martinovic J, Bénéteau C, Molin A, Carles D, André G, Bieth E, Chassaing N, Devisme L, Chalabreysse L, Pasquier L, Secq V, Don M, Orsaria M, Missirian C, Mortreux J, Sanlaville D, Pons L, Küry S, Bézieau S, Liet JM, Joram N, Bihouée T, Scott DA, Brown CW, Scaglia F, Tsai AC, Grange DK, Phillips JA, Pfotenhauer JP, Jhangiani SN, Gonzaga-Jauregui CG, Chung WK, Schauer GM, Lipson MH, Mercer CL, van Haeringen A, Liu Q, Popek E, Coban Akdemir ZH, Lupski JR, Szafranski P, Isidor B, Le Caignec C & Stankiewicz P. (2019). Complex Compound Inheritance of Lethal Lung Developmental Disorders due to Disruption of the TBX-FGF Pathway. Am. J. Hum. Genet. , , . PMID: 30639323 DOI.
Complex Compound Inheritance of Lethal Lung Developmental Disorders Due to Disruption of the TBX-FGF Pathway
Abstract Primary defects in lung branching morphogenesis, resulting in neonatal lethal pulmonary hypoplasias, are incompletely understood. To elucidate the pathogenetics of human lung development, we studied a unique collection of samples obtained from deceased individuals with clinically and histopathologically diagnosed interstitial neonatal lung disorders: acinar dysplasia (n = 14), congenital alveolar dysplasia (n = 2), and other lethal lung hypoplasias (n = 10). We identified rare heterozygous copy-number variant deletions or single-nucleotide variants (SNVs) involving TBX4 (n = 8 and n = 2, respectively) or FGF10 (n = 2 and n = 2, respectively) in 16/26 (61%) individuals. In addition to TBX4, the overlapping ∼2 Mb recurrent and nonrecurrent deletions at 17q23.1q23.2 identified in seven individuals with lung hypoplasia also remove a lung-specific enhancer region. Individuals with coding variants involving either TBX4 or FGF10 also harbored at least one non-coding SNV in the predicted lung-specific enhancer region, which was absent in 13 control individuals with the overlapping deletions but without any structural lung anomalies. The occurrence of rare coding variants involving TBX4 or FGF10 with the putative hypomorphic non-coding SNVs implies a complex compound inheritance of these pulmonary hypoplasias. Moreover, they support the importance of TBX4-FGF10-FGFR2 epithelial-mesenchymal signaling in human lung organogenesis and help to explain the histopathological continuum observed in these rare lethal developmental disorders of the lung. Copyright © 2018 American Society of Human Genetics. Published by Elsevier Inc. All rights reserved. KEYWORDS: 17q23.1q23.2 recurrent deletion; 5p12 deletion; T-box transcription factor 4; aplasia of lacrimal and salivary glands; fibroblast growth factor 10; lacrimoauriculodentodigital (LAAD) syndrome; lung hypoplasia; neonatal lung disease PMID: 30639323 PMCID: PMC6369446 DOI: 10.1016/j.ajhg.2018.12.010
Review - T-Box Genes in the Kidney and Urinary Tract
Curr Top Dev Biol. 2017;122:245-278. doi: 10.1016/bs.ctdb.2016.06.002. Epub 2016 Jul 27.
T-box (Tbx) genes encode an ancient group of transcription factors that play important roles in patterning, specification, proliferation, and differentiation programs in vertebrate organogenesis. This is testified by severe organ malformation syndromes in mice homozygous for engineered null alleles of specific T-box genes and by the large number of human inherited organ-specific diseases that have been linked to mutations in these genes. One of the organ systems that has not been associated with loss of specific T-box gene function in human disease for long is the excretory system. However, this has changed with the finding that mutations in TBX18, a member of a vertebrate-specific subgroup within the Tbx1-subfamily of T-box transcription factor genes, cause congenital anomalies of the kidney and urinary tract, predominantly hydroureter and ureteropelvic junction obstruction. Gene expression analyses, loss-of-function studies, and lineage tracing in the mouse suggest a primary role for this transcription factor in specifying the ureteric mesenchyme in the common anlage of the kidney, the ureter, and the bladder. We review the function of Tbx18 in ureterogenesis and discuss the body of evidence that Tbx18 and other members of the T-box gene family, namely, Tbx1, Tbx2, Tbx3, and Tbx20, play additional roles in development and homeostasis of other components of the excretory system in vertebrates. © 2017 Elsevier Inc. All rights reserved.
KEYWORDS: Bladder; Cloaca; Development; Excretory system; Pronephros; T-Box; Tbx; Tbx1; Tbx18; Tbx2; Tbx20; Tbx3; Ureter; Urinary system PMID 28057266 DOI: 10.1016/bs.ctdb.2016.06.002
The T-box gene family: emerging roles in development, stem cells and cancer
Development. 2014 Oct;141(20):3819-33. doi: 10.1242/dev.104471.
The T-box family of transcription factors exhibits widespread involvement throughout development in all metazoans. T-box proteins are characterized by a DNA-binding motif known as the T-domain that binds DNA in a sequence-specific manner. In humans, mutations in many of the genes within the T-box family result in developmental syndromes, and there is increasing evidence to support a role for these factors in certain cancers. In addition, although early studies focused on the role of T-box factors in early embryogenesis, recent studies in mice have uncovered additional roles in unsuspected places, for example in adult stem cell populations. Here, I provide an overview of the key features of T-box transcription factors and highlight their roles and mechanisms of action during various stages of development and in stem/progenitor cell populations. © 2014. Published by The Company of Biologists Ltd. KEYWORDS: T-box genes; Tbx; Transcription factors
Tbx1 controls the morphogenesis of pharyngeal pouch epithelia through mesodermal Wnt11r and Fgf8a
Development. 2014 Sep;141(18):3583-93. doi: 10.1242/dev.111740. Epub 2014 Aug 19.
Choe CP1, Crump JG2.
The pharyngeal pouches are a segmental series of epithelial structures that organize the embryonic vertebrate face. In mice and zebrafish that carry mutations in homologs of the DiGeorge syndrome gene TBX1, a lack of pouches correlates with severe craniofacial defects, yet how Tbx1 controls pouch development remains unclear. Using mutant and transgenic rescue experiments in zebrafish, we show that Tbx1 functions in the mesoderm to promote the morphogenesis of pouch-forming endoderm through wnt11r and fgf8a expression. Consistently, compound losses of wnt11r and fgf8a phenocopy tbx1 mutant pouch defects, and mesoderm-specific restoration of Wnt11r and Fgf8a rescues tbx1 mutant pouches. Time-lapse imaging further reveals that Fgf8a acts as a Wnt11r-dependent guidance cue for migrating pouch cells. We therefore propose a two-step model in which Tbx1 coordinates the Wnt-dependent epithelial destabilization of pouch-forming cells with their collective migration towards Fgf8a-expressing mesodermal guideposts. © 2014. Published by The Company of Biologists Ltd. KEYWORDS: Epithelial morphogenesis; Fgf8; Pharyngeal pouches; Tbx1; Wnt11r; Zebrafish
Conditional and constitutive expression of a Tbx1-GFP fusion protein in mice
BMC Dev Biol. 2013 Aug 23;13(1):33. [Epub ahead of print] Freyer L, Nowotschin S, Pirity MK, Baldini A, Morrow BE.
BACKGROUND: Velo-cardio-facial syndrome/DiGeorge syndrome (VCFS/DGS) is caused by a 1.5-3 Mb microdeletion of chromosome 22q11.2, frequently referred to as 22q11.2 deletion syndrome (22q11DS). This region includes TBX1, a T-box transcription factor gene that contributes to the etiology of 22q11DS. The requirement for TBX1 in mammalian development is dosage-sensitive, such that loss-of-function (LOF) and gain-of-function (GOF) of TBX1 in both mice and humans results in disease relevant congenital malformations. RESULTS: To further gain insight into the role of Tbx1 in development, we have targeted the Rosa26 locus to generate a new GOF mouse model in which a Tbx1-GFP fusion protein is expressed conditionally using the Cre/LoxP system. Tbx1-GFP expression is driven by the endogenous Rosa26 promoter resulting in ectopic and persistent expression. Tbx1 is pivotal for proper ear and heart development; ectopic activation of Tbx1-GFP in the otic vesicle by Pax2-Cre and Foxg1-Cre represses neurogenesis and produces morphological defects of the inner ear. Overexpression of a single copy of Tbx1-GFP using Tbx1Cre/+ was viable, while overexpression of both copies resulted in neonatal lethality with cardiac outflow tract defects. We have partially rescued inner ear and heart anomalies in Tbx1Cre/- null embryos by expression of Tbx1-GFP. CONCLUSIONS: We have generated a new mouse model to conditionally overexpress a GFP-tagged Tbx1 protein in vivo. This provides a useful tool to investigate in vivo direct downstream targets and protein binding partners of Tbx1.
Tbx1 regulates oral epithelial adhesion and palatal development
Hum Mol Genet. 2012 Jun 1;21(11):2524-37. doi: 10.1093/hmg/dds071. Epub 2012 Feb 27.
Funato N, Nakamura M, Richardson JA, Srivastava D, Yanagisawa H. Source Human Gene Sciences Center, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510, Japan.
Cleft palate, the most frequent congenital craniofacial birth defect, is a multifactorial condition induced by the interaction of genetic and environmental factors. In addition to complete cleft palate, a large number of human cases involve soft palate cleft and submucosal cleft palate. However, the etiology of these forms of cleft palate has not been well understood. T-box transcriptional factor (Tbx) family of transcriptional factors has distinct roles in a wide range of embryonic differentiation or response pathways. Here, we show that genetic disruption of Tbx1, a major candidate gene for the human congenital disorder 22q11.2 deletion syndrome (Velo-cardio-facial/DiGeorge syndrome), led to abnormal epithelial adhesion between the palate and mandible in mouse, resulting in various forms of cleft palate similar to human conditions. We found that hyperproliferative epithelium failed to undergo complete differentiation in Tbx1-null mice (Tbx1(-/-)). Inactivation of Tbx1 specifically in the keratinocyte lineage (Tbx1(KCKO)) resulted in an incomplete cleft palate confined to the anterior region of the palate. Interestingly, Tbx1 overexpression resulted in decreased cell growth and promoted cell-cycle arrest in MCF7 epithelial cells. These findings suggest that Tbx1 regulates the balance between proliferation and differentiation of keratinocytes and is essential for palatal fusion and oral mucosal differentiation. The impaired adhesion separation of the oral epithelium together with compromised palatal mesenchymal growth is an underlying cause for various forms of cleft palate phenotypes in Tbx1(-/-) mice. Our present study reveals new pathogenesis of incomplete and submucous cleft palate during mammalian palatogenesis.
Tbx1 is a negative modulator of Mef2c
Hum Mol Genet. 2012 Jun 1;21(11):2485-96. doi: 10.1093/hmg/dds063. Epub 2012 Feb 24.
Pane LS, Zhang Z, Ferrentino R, Huynh T, Cutillo L, Baldini A. Source Institute of Genetics and Biophysics, National Research Council, 80131 Naples, Italy.
The developmental role of the T-box transcription factor Tbx1 is exquisitely dosage-sensitive. In this study, we performed a microarray-based transcriptome analysis of E9.5 embryo tissues across a previously generated Tbx1 mouse allelic series. This analysis identified several genes whose expression was affected by Tbx1 dosage. Interestingly, we found that the expression of the gene encoding the cardiogenic transcription factor Mef2c was negatively correlated to Tbx1 dosage. In vivo data revealed Mef2c up-regulation in the second heart field (SHF) of Tbx1 null mutant embryos compared with wild-type littermates at E9.5. Conversely, Mef2c expression was decreased in the SHF and in somites of Tbx1 gain-of-function mutants. These results are consistent with the described role of Tbx1 in suppressing cardiac progenitor cell differentiation and indicate also a negative effect of Tbx1 on Mef2c during skeletal muscle differentiation. We show that Tbx1 occupies conserved regulatory regions of the Mef2c locus, suggesting a direct effect on Mef2c transcription. However, we also show that Tbx1 interferes with the Gata4→ Mef2c regulatory pathway. Overall, our study uncovered a target of Tbx1 with critical developmental roles, so highlighting the power of the dosage gradient approach that we used.
Nadine Dobrovolskaïa-Zavadskaïa and the dawn of developmental genetics
Bioessays. 2001 Apr;23(4):365-71.
Korzh V1, Grunwald D.
In one of the first genetic screens aimed at identifying induced developmental mutants, Nadine Dobrovolskaïa-Zavadskaïa, working at the Pasteur Laboratory in the 1920s, isolated and characterized a mutation affecting Brachyury, a gene that regulates tail and axial development in the mouse. Dobrovolskaïa-Zavadskaïa's analysis of Brachyury and other mutations affecting tail development were among the earliest attempts to link gene action with a tissue-specific developmental process in a vertebrate. Her analyses of genes that interacted with Brachyury led to the discovery of the t-haplotype chromosome of mouse. After 70 years, Brachyury and the multiple genes with which it interacts continue to occupy a prominent focus in developmental biology research. A goal of this review is to identify the contributions that Dobrovolskaïa-Zavadskaïa made to our current thinking about Brachyury and how she helped to shape the dawn of the field of developmental genetics. BioEssays 23:365-371, 2001.
Copyright 2001 John Wiley & Sons, Inc.