1
|
Liang Y, Wu H, He X, He X. Case Report: Aarskog-scott syndrome caused by FGD1 gene variation: A family study. Front Genet 2022; 13:932073. [PMID: 36051692 PMCID: PMC9424661 DOI: 10.3389/fgene.2022.932073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 07/07/2022] [Indexed: 11/13/2022] Open
Abstract
Aarskog-Scott syndrome is a rare genetic disorder characterized by short stature, abnormal facial features, and digital and genital deformities. FGD1 gene variation is the known cause of this disorder. This paper described a Chinese family study of Aarskog-Scott syndrome in which the main patients were two brothers. Then, the relationship between genotype and phenotype in Aarskog-Scott syndrome was investigated preliminarily. A new FGD1 gene variant was revealed in this study, providing insights into the link between phenotype and genotype variations in Aarskog-Scott syndrome as well as a foundation for its diagnosis and treatment.
Collapse
Affiliation(s)
- Yijia Liang
- Fifth Medical Center of Chinese PLA General Hospital, Beijing, China
- Chinese PLA Medical College, Beijing, China
| | - Honglin Wu
- Fifth Medical Center of Chinese PLA General Hospital, Beijing, China
| | - Xiumei He
- Fifth Medical Center of Chinese PLA General Hospital, Beijing, China
| | - Xiyu He
- Fifth Medical Center of Chinese PLA General Hospital, Beijing, China
- *Correspondence: Xiyu He,
| |
Collapse
|
2
|
Reinhard NR, Van Der Niet S, Chertkova A, Postma M, Hordijk PL, Gadella TWJ, Goedhart J. Identification of guanine nucleotide exchange factors that increase Cdc42 activity in primary human endothelial cells. Small GTPases 2019; 12:226-240. [PMID: 31469028 PMCID: PMC7939571 DOI: 10.1080/21541248.2019.1658509] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The Rho GTPase family is involved in actin dynamics and regulates the barrier function of the endothelium. One of the main barrier-promoting Rho GTPases is Cdc42, also known as cell division control protein 42 homolog. Currently, regulation of Cdc42-based signalling networks in endothelial cells (ECs) lack molecular details. To examine these, we focused on a subset of 15 Rho guanine nucleotide exchange factors (GEFs), which are expressed in the endothelium. By performing single cell FRET measurements with Rho GTPase biosensors in primary human ECs, we monitored GEF efficiency towards Cdc42 and Rac1. A new, single cell-based analysis was developed and used to enable the quantitative comparison of cellular activities of the overexpressed full-length GEFs. Our data reveal GEF dependent activation of Cdc42, with the most efficient Cdc42 activation induced by PLEKHG2, FGD1, PLEKHG1 and PREX1 and the highest selectivity for FGD1. Additionally, we generated truncated GEF constructs that comprise only the catalytic dbl homology (DH) domain or together with the adjacent pleckstrin homology domain (DHPH). The DH domain by itself did not activate Cdc42, whereas the DHPH domain of ITSN1, ITSN2 and PLEKHG1 showed activity towards Cdc42. Together, our study characterized endothelial GEFs that may directly or indirectly activate Cdc42, which will be of great value for the field of vascular biology.
Collapse
Affiliation(s)
- Nathalie R Reinhard
- Molecular Cytology, Swammerdam Institute for Life Sciences, van Leeuwenhoek Centre for Advanced Microscopy, University of Amsterdam, Amsterdam, The Netherlands
| | - Sanne Van Der Niet
- Molecular Cytology, Swammerdam Institute for Life Sciences, van Leeuwenhoek Centre for Advanced Microscopy, University of Amsterdam, Amsterdam, The Netherlands
| | - Anna Chertkova
- Molecular Cytology, Swammerdam Institute for Life Sciences, van Leeuwenhoek Centre for Advanced Microscopy, University of Amsterdam, Amsterdam, The Netherlands
| | - Marten Postma
- Molecular Cytology, Swammerdam Institute for Life Sciences, van Leeuwenhoek Centre for Advanced Microscopy, University of Amsterdam, Amsterdam, The Netherlands
| | - Peter L Hordijk
- Molecular Cytology, Swammerdam Institute for Life Sciences, van Leeuwenhoek Centre for Advanced Microscopy, University of Amsterdam, Amsterdam, The Netherlands.,Department of Physiology, Amsterdam University Medical Center, location VUmc, Amsterdam, The Netherlands
| | - Theodorus W J Gadella
- Molecular Cytology, Swammerdam Institute for Life Sciences, van Leeuwenhoek Centre for Advanced Microscopy, University of Amsterdam, Amsterdam, The Netherlands
| | - Joachim Goedhart
- Molecular Cytology, Swammerdam Institute for Life Sciences, van Leeuwenhoek Centre for Advanced Microscopy, University of Amsterdam, Amsterdam, The Netherlands
| |
Collapse
|
3
|
Dental and Maxillofacial Signs in Aarskog Syndrome: A Review of 3 Siblings and the Literature. J Oral Maxillofac Surg 2018; 76:2202-2208. [DOI: 10.1016/j.joms.2018.03.027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Revised: 03/21/2018] [Accepted: 03/21/2018] [Indexed: 11/18/2022]
|
4
|
Ge Y, Li N, Wang Z, Wang J, Cai H. Novel variant in the FGD1 gene causing Aarskog-Scott syndrome. Exp Ther Med 2017; 13:2623-2628. [PMID: 28587322 PMCID: PMC5450764 DOI: 10.3892/etm.2017.4301] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2015] [Accepted: 10/11/2016] [Indexed: 11/05/2022] Open
Abstract
Aarskog-Scott syndrome (ASS) is a rare, X-linked recessive inherited disorder. Affected individuals may develop short stature and exhibit distinctive skeletal and genital development. Mutations in the FYVE, rhogef and pleckstrin homology domain-containing protein 1 (FGD1) gene, located within the Xp11.21 region, are responsible for the occurrence of ASS. Since it is rare and complex, it can take a long time to obtain a definitive clinical diagnosis unless clinicians are familiar with the disease. In the present study, whole-exome sequencing (WES) was performed to screen for causal variants in a Chinese pediatric patient who exhibited a number of clinical symptoms of ASS, including short stature, facial abnormalities, stubby metacarpals and swollen testis. DNA sequencing revealed a novel c.1270 A>G mutation in exon 6 of the FGD1 gene, which led to an amino acid conversion of asparagine to aspartic acid on codon 424 and in silico analysis indicated that this novel missense mutation was pathogenic. The present study identified a novel variant of the FGD1 gene and to the best of our knowledge, is the first report of ASS in a Chinese individual. The results indicated that WES is an effective tool for the diagnosis of rare and complex syndromes such as ASS.
Collapse
Affiliation(s)
- Yihua Ge
- Department of Pediatric Orthopedics, Shanghai Children's Medical Center, Shanghai Jiaotong University School of Medicine, Shanghai 200127, P.R. China
| | - Niu Li
- Institute of Pediatric Translational Medicine, Shanghai Children's Medical Center, Shanghai Jiaotong University School of Medicine, Shanghai 200127, P.R. China
| | - Zhigang Wang
- Department of Pediatric Orthopedics, Shanghai Children's Medical Center, Shanghai Jiaotong University School of Medicine, Shanghai 200127, P.R. China
| | - Jian Wang
- Institute of Pediatric Translational Medicine, Shanghai Children's Medical Center, Shanghai Jiaotong University School of Medicine, Shanghai 200127, P.R. China
| | - Haiqing Cai
- Department of Pediatric Orthopedics, Shanghai Children's Medical Center, Shanghai Jiaotong University School of Medicine, Shanghai 200127, P.R. China
| |
Collapse
|
5
|
Parıltay E, Hazan F, Ataman E, Demir K, Etlik Ö, Özbek E, Özkan B. A novel splice site mutation of FGD1 gene in an Aarskog-Scott syndrome patient with a large anterior fontanel. J Pediatr Endocrinol Metab 2016; 29:1111-4. [PMID: 27544718 DOI: 10.1515/jpem-2015-0482] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Accepted: 07/18/2016] [Indexed: 11/15/2022]
Abstract
Aarskog-Scott syndrome (ASS) is a rare X-linked recessive genetic disorder caused by FGD1 mutations. FGD1 regulates the actin cytoskeleton and regulates cell growth and differentiation by activating the c-Jun N-terminal kinase signaling cascade. ASS is characterized by craniofacial dysmorphism, short stature, interdigital webbing and shawl scrotum. However, there is a wide phenotypic heterogeneity because of the additional clinical features. ASS and some syndromes including the autosomal dominant inherited form of Robinow syndrome, Noonan syndrome, pseudohypoparathyroidism, Silver-Russel and SHORT syndrome have some overlapping phenotypic features. Herein, we report a patient with ASS and a large anterior fontanel who was initially diagnosed as Robinow syndrome. He was found to have a novel c.1340+2 T>A splice site mutation on the FGD1 gene.
Collapse
MESH Headings
- Abnormalities, Multiple/genetics
- Abnormalities, Multiple/pathology
- Alternative Splicing/genetics
- Cranial Fontanelles/pathology
- Craniofacial Abnormalities/complications
- Craniofacial Abnormalities/genetics
- Craniofacial Abnormalities/pathology
- Dwarfism/complications
- Dwarfism/genetics
- Dwarfism/pathology
- Face/abnormalities
- Face/pathology
- Genetic Diseases, X-Linked/complications
- Genetic Diseases, X-Linked/genetics
- Genetic Diseases, X-Linked/pathology
- Genitalia, Male/abnormalities
- Genitalia, Male/pathology
- Guanine Nucleotide Exchange Factors/genetics
- Hand Deformities, Congenital/complications
- Hand Deformities, Congenital/genetics
- Hand Deformities, Congenital/pathology
- Heart Defects, Congenital/complications
- Heart Defects, Congenital/genetics
- Heart Defects, Congenital/pathology
- Humans
- Infant, Newborn
- Limb Deformities, Congenital/complications
- Limb Deformities, Congenital/genetics
- Limb Deformities, Congenital/pathology
- Male
- Mutation/genetics
- Prognosis
- Urogenital Abnormalities/complications
- Urogenital Abnormalities/genetics
- Urogenital Abnormalities/pathology
Collapse
|
6
|
Clinical utility gene card for: Aarskog-Scott Syndrome (faciogenital dysplasia) - update 2015. Eur J Hum Genet 2014; 23:ejhg2014178. [PMID: 25227149 DOI: 10.1038/ejhg.2014.178] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Revised: 08/01/2014] [Accepted: 08/06/2014] [Indexed: 11/08/2022] Open
|
7
|
Aten E, Sun Y, Almomani R, Santen GWE, Messemaker T, Maas SM, Breuning MH, den Dunnen JT. Exome sequencing identifies a branch point variant in Aarskog-Scott syndrome. Hum Mutat 2012; 34:430-4. [PMID: 23169394 DOI: 10.1002/humu.22252] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2012] [Accepted: 11/08/2012] [Indexed: 11/07/2022]
Abstract
Aarskog-Scott syndrome (ASS) is a rare disorder with characteristic facial, skeletal, and genital abnormalities. Mutations in the FGD1 gene (Xp11.21) are responsible for ASS. However, mutation detection rates are low. Here, we report a family with ASS where conventional Sanger sequencing failed to detect a pathogenic change in FGD1. To identify the causative gene, we performed whole-exome sequencing in two patients. An initial analysis did not reveal a likely candidate gene. After relaxing our filtering criteria, accepting larger intronic segments, we unexpectedly identified a branch point (BP) variant in FGD1. Analysis of patient-derived RNA showed complete skipping of exon 13, leading to premature translation termination. The BP variant detected is one of very few reported so far proven to affect splicing. Our results show that besides digging deeper to reveal nonobvious variants, isolation and analysis of RNA provides a valuable but under-appreciated tool to resolve cases with unknown genetic defects.
Collapse
MESH Headings
- Abnormalities, Multiple/diagnosis
- Abnormalities, Multiple/genetics
- Dwarfism/diagnosis
- Dwarfism/genetics
- Exome
- Exons
- Face/abnormalities
- Female
- Genetic Diseases, X-Linked/diagnosis
- Genetic Diseases, X-Linked/genetics
- Genitalia, Male/abnormalities
- Guanine Nucleotide Exchange Factors/genetics
- Hand Deformities, Congenital/diagnosis
- Hand Deformities, Congenital/genetics
- Heart Defects, Congenital/diagnosis
- Heart Defects, Congenital/genetics
- Humans
- Male
- Mutation
- Phenotype
- Polymorphism, Single Nucleotide
- Sequence Analysis, DNA/methods
- Sequence Analysis, RNA/methods
Collapse
Affiliation(s)
- Emmelien Aten
- Center for Human and Clinical Genetics, Leiden University Medical Center, Leiden, the Netherlands
| | | | | | | | | | | | | | | |
Collapse
|
8
|
Pilozzi-Edmonds L, Maher TA, Basran RK, Milunsky A, Al-Thihli K, Braverman NE, Alfares A. Fraternal twins with Aarskog-Scott syndrome due to maternal germline mosaicism. Am J Med Genet A 2011; 155A:1987-90. [DOI: 10.1002/ajmg.a.34094] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2011] [Revised: 04/11/2011] [Accepted: 04/13/2011] [Indexed: 11/06/2022]
|
9
|
Gao L, Gorski JL, Chen CS. The Cdc42 guanine nucleotide exchange factor FGD1 regulates osteogenesis in human mesenchymal stem cells. THE AMERICAN JOURNAL OF PATHOLOGY 2011; 178:969-74. [PMID: 21356349 DOI: 10.1016/j.ajpath.2010.11.051] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 04/26/2010] [Revised: 10/22/2010] [Accepted: 11/15/2010] [Indexed: 10/18/2022]
Abstract
Loss of function mutations in FGD1 result in faciogenital dysplasia, an X-linked human developmental disorder that adversely affects the formation of multiple skeletal structures. FGD1 encodes a guanine nucleotide exchange factor that specifically activates Cdc42, a Rho family small GTPase that regulates a variety of cellular behaviors. We have found that FGD1 is expressed in human mesenchymal stem cells (hMSCs) isolated from adult bone marrow. hMSCs are multipotent cells that can differentiate into many cell types, including fibroblasts, osteoblasts, adipocytes, and chondrocytes, and are thought to play a role in maintaining musculoskeletal tissues throughout life. We demonstrate an active role of FGD1 in osteogenic differentiation of hMSCs. During osteogenic differentiation of hMSCs in culture, we observed up-regulation of both FGD1 expression and Cdc42 activity. Activating FGD1/Cdc42 signaling by overexpression of either FGD1 or constitutively active Cdc42 promoted hMSC osteogenesis, while inhibiting Cdc42 signaling by either dominant negative mutants of FGD1 or Cdc42 suppressed osteogenesis. These results demonstrate an important role for FGD1/Cdc42 signaling in hMSC osteogenesis and suggest that the defects in bone remodeling in faciogenital dysplasia may persist throughout adult life and serve as a potential pathway that may be targeted for enhancing bone regeneration.
Collapse
Affiliation(s)
- Lin Gao
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | | | | |
Collapse
|
10
|
Oshima T, Fujino T, Ando K, Hayakawa M. Role of FGD1, a Cdc42 Guanine Nucleotide Exchange Factor, in Epidermal Growth Factor-Stimulated c-Jun NH2-Terminal Kinase Activation and Cell Migration. Biol Pharm Bull 2011; 34:54-60. [DOI: 10.1248/bpb.34.54] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Toshiyuki Oshima
- School of Pharmacy, Tokyo University of Pharmacy and Life Sciences
| | - Tomofumi Fujino
- School of Pharmacy, Tokyo University of Pharmacy and Life Sciences
| | - Ken Ando
- School of Pharmacy, Tokyo University of Pharmacy and Life Sciences
| | - Makio Hayakawa
- School of Pharmacy, Tokyo University of Pharmacy and Life Sciences
| |
Collapse
|
11
|
Oshima T, Fujino T, Ando K, Hayakawa M. Proline-rich domain plays a crucial role in extracellular stimuli-responsive translocation of a Cdc42 guanine nucleotide exchange factor, FGD1. Biol Pharm Bull 2010; 33:35-9. [PMID: 20045932 DOI: 10.1248/bpb.33.35] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We previously demonstrated that FGD1, the Cdc42 guanine nucleotide exchange factor (GEF) responsible for faciogenital dysplasia, and its homologue FGD3 are targeted by the ubiquitin ligase SCF(FWD1) upon phosphorylation of two serine residues in their DSGIDS motif and subsequently degraded by the proteasome. FGD1 and FGD3 share highly homologous Dbl homology (DH) and adjacent pleckstrin homology (PH) domains, both of which are responsible for GEF activity. However, their function and regulation are remarkably different. Here we demonstrate extracellular signal-responsive translocation of FGD1, but not FGD3. During the wound-healing process, translocation of FGD1 to the leading edge membrane occurs in cells facing to the wound. Furthermore, epidermal growth factor (EGF) stimulates the membrane translocation of FGD1, but not FGD3. As the most striking difference, FGD3 lacks the N-terminal proline-rich domain that is conserved in FGD1, indicating that proline-rich domain may play a crucial role in signal-responsive translocation of FGD1. Indeed, there is a faciogenital dysplasia patient who has a missense mutation in proline-rich domain of FGD1, by which the serine residue at position 205 is substituted with isoleucine. When expressed in cells, the mutant FGD1 with S(205)/I substitution fails to translocate to the membrane in response to the mitogenic stimuli. Thus we present a novel mechanism by which the activity of FGD1, a GEF for Cdc42, is temporally and spatially regulated in cells.
Collapse
Affiliation(s)
- Toshiyuki Oshima
- School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, Tokyo, Japan
| | | | | | | |
Collapse
|
12
|
Ayala I, Giacchetti G, Caldieri G, Attanasio F, Mariggiò S, Tetè S, Polishchuk R, Castronovo V, Buccione R. Faciogenital Dysplasia Protein Fgd1 Regulates Invadopodia Biogenesis and Extracellular Matrix Degradation and Is Up-regulated in Prostate and Breast Cancer. Cancer Res 2009; 69:747-52. [DOI: 10.1158/0008-5472.can-08-1980] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
13
|
Abstract
Both Aarskog syndrome and atraumatic anterior hip dislocation are rare entities. Aarskog syndrome is an X-linked recessive disorder with facial, digital, and genital anomalies and is associated with varying degrees of ligamentous laxity. This is believed to be the only known reported case of bilateral anterior voluntary dislocating hips in an ambulatory child and the only reported case of hip dislocation in a child with Aarskog syndrome. Staged bilateral varus derotational femoral osteotomies and Dega osteotomies were successfully performed. Hardware was removed 1 year after the second operation. The patient has been asymptomatic at 2 years' follow-up. This article calls attention to the features of Aarskog syndrome and potential orthopaedic concerns.
Collapse
|
14
|
Nakanishi H, Takai Y. Frabin and other related Cdc42-specific guanine nucleotide exchange factors couple the actin cytoskeleton with the plasma membrane. J Cell Mol Med 2008; 12:1169-76. [PMID: 18410521 PMCID: PMC3865658 DOI: 10.1111/j.1582-4934.2008.00345.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Frabin, together with, at least, FGD1, FGD2, FGD3 and FGD1-related Cdc42-GEF (FRG), is a member of a family of Cdc42-specific gua-nine nucleotide exchange factors (GEFs). These proteins have multiple phosphoinositide-binding domains, including two pleckstrin homology (PH) domains and an FYVE or FERM domain. It is likely that they couple the actin cytoskeleton with the plasma membrane. Frabin associates with a specific actin structure(s) and induces the direct activation of Cdc42 in the vicinity of this structure(s), resulting in actin reorganization. Furthermore, frabin associates with a specific membrane structure(s) and induces the indirect activation of Rac in the vicinity of this structure(s), resulting in the reorganization of the actin cytoskeleton. This reorganization of the actin cytoskeleton induces cell shape changes such as the formation of filopodia and lamellipodia.
Collapse
Affiliation(s)
- Hiroyuki Nakanishi
- Department of Molecular Pharmacology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
| | | |
Collapse
|
15
|
van Galen EJM, Ramakers GJA. Rho proteins, mental retardation and the neurobiological basis of intelligence. PROGRESS IN BRAIN RESEARCH 2005; 147:295-317. [PMID: 15581714 DOI: 10.1016/s0079-6123(04)47022-8] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
For several decades it has been known that mental retardation is associated with abnormalities in dendrites and dendritic spines. The recent cloning of eight genes which cause nonspecific mental retardation when mutated, provides an important insight into the cellular mechanisms that result in the dendritic abnormalities underlying mental retardation. Three of the encoded proteins, oligophrenin1, PAK3 and alphaPix, interact directly with Rho GTPases. Rho GTPases are key signaling proteins which integrate extracellular and intracellular signals to orchestrate coordinated changes in the actin cytoskeleton, essential for directed neurite outgrowth and the generation/rearrangement of synaptic connectivity. Although many details of the cell biology of Rho signaling in the CNS are as yet unclear, a picture is unfolding showing how mutations that cause abnormal Rho signaling result in abnormal neuronal connectivity which gives rise to deficient cognitive functioning in humans.
Collapse
Affiliation(s)
- Elly J M van Galen
- Neurons and Networks Research Group, Netherlands Institute for Brain Research, Graduate School Neurosciences Amsterdam, Meibergdreef 33, 1105 AZ Amsterdam ZO, The Netherlands
| | | |
Collapse
|
16
|
Abstract
The human faciogenital dysplasia 1 (FGD1) gene product plays an important role in morphogenesis. Its dysfunction causes Aarskog-Scott syndrome (MIM musical sharp 305400). To characterize the FGD1, we investigated its expression by RT-PCR and Southern blot analysis in normal tissues. We found novel alternative forms of the FGD1. One has a novel exon located in intron 8, named exon 8B (8B FDG1) and the other has an exon in intron 7, exon 7B (7B FGD1). The 8B FDG1 is expressed strongly in the brain, testis, spinal cord, trachea and stomach, and weakly in the thymus and lymphocytes. However, expression of the 7B FGD1 is weak and restricted in the testis and salivary gland. Insertion of each novel exon results in production of a premature termination codon, respectively, and the predicted proteins generated from them have only a proline-rich domain and an incomplete DH domain which potentially compete with the wild type of FGD1.
Collapse
Affiliation(s)
- Kumiko Yanagi
- Department of Medical Genetics, University of Ryukyus Graduate School of Medicine, Okinawa, Japan
| | | | | | | |
Collapse
|
17
|
Abstract
Cognitive disorders in children have traditionally been described in terms of clinical phenotypes or syndromes, chromosomal lesions, metabolic disorders, or neuropathology. Relatively little is known about how these disorders affect the chemical reactions involved in learning and memory. Experiments in fruit flies, snails, and mice have revealed some highly conserved pathways that are involved in learning, memory, and synaptic plasticity, which is the primary substrate for memory storage. These can be divided into short-term memory storage through local changes in synapses, and long-term storage mediated by activation of transcription to translate new proteins that modify synaptic function. This review summarizes evidence that disruptions in these pathways are involved in human cognitive disorders, including neurofibromatosis type I, Coffin-Lowry syndrome, Rubinstein-Taybi syndrome, Rett syndrome, tuberous sclerosis-2, Down syndrome, X-linked alpha-thalassemia/mental retardation, cretinism, Huntington disease, and lead poisoning.
Collapse
Affiliation(s)
- Michael V Johnston
- Division of Neurology and Developmental Medicine, Kennedy Krieger Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
| | | | | |
Collapse
|
18
|
Abstract
Plasticity includes the brain's capacity to be shaped or moulded by experience, the capacity to learn and remember, and the ability to reorganize and recover after injury. Mechanisms for plasticity include activity-dependent refinement of neuronal connections and synaptic plasticity as a substrate for learning and memory. The molecular mechanisms for these processes utilize signalling cascades that relay messages from synaptic receptors to the nucleus and the cytoskeleton to control the structure of axons and dendrites. Several paediatric neurological disorders such as neurofibromatosis-1, Fragile X syndrome, Rett syndrome, and other syndromic and non-specific forms of mental retardation involve lesions in these signalling pathways. Acquired disorders such as hypoxic-ischaemic encephalopathy, lead poisoning and epilepsy also involve signalling pathways including excitatory glutamate receptors. Information about these 'plasticity pathways' is useful for understanding their pathophysiology and potential therapy.
Collapse
Affiliation(s)
- Michael V Johnston
- Department of Neurology and Developmental Medicine, Kennedy Krieger Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| |
Collapse
|
19
|
Gampel A, Mellor H. Small interfering RNAs as a tool to assign Rho GTPase exchange-factor function in vivo. Biochem J 2002; 366:393-8. [PMID: 12113653 PMCID: PMC1222811 DOI: 10.1042/bj20020844] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2002] [Revised: 07/04/2002] [Accepted: 07/12/2002] [Indexed: 11/17/2022]
Abstract
Rho GTPases control a complex network of intracellular signalling pathways. Whereas progress has been made in identifying downstream signalling partners for these proteins, the characterization of Rho upstream regulatory guanine-nucleotide exchange factors (GEFs) has been hampered by a lack of suitable research tools. Here we use small interfering RNAs (siRNAs) to examine the cellular regulation of the RhoB GTPase, and show that RhoB is activated downstream of the epidermal-growth-factor receptor through the Vav2 exchange factor. These studies demonstrate that siRNAs are an ideal research tool for the assignment of Rho GEF function in vivo.
Collapse
Affiliation(s)
- Alexandra Gampel
- Mammalian Cell Biology Laboratory, Department of Biochemistry, School of Medical Sciences, University of Bristol, Bristol BS8 1TD, UK
| | | |
Collapse
|
20
|
Armstrong PJ, Johanning JM, Calton WC, Delatore JR, Franklin DP, Han DC, Carey DJ, Elmore JR. Differential gene expression in human abdominal aorta: aneurysmal versus occlusive disease. J Vasc Surg 2002; 35:346-55. [PMID: 11854734 DOI: 10.1067/mva.2002.121071] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
OBJECTIVE Inflammation and atherosclerosis are present in both abdominal aortic aneurysm (AAA) and arterial occlusive disease (AOD). Changes in gene expression that underlie the development of AAA versus AOD are poorly defined. This study evaluated differences in gene expression in AAA, AOD, and control aortic tissue with human gene array technology. METHODS RNA was isolated from human aortic specimens (seven AAA, five AOD, and five control), and complementary DNA (cDNA) probes were generated. The cDNA probes were hybridized to a human cell interaction array of 265 genes and quantitated with phosphorimaging. The data were corrected for background and were standardized to housekeeping genes. Statistical differences in individual gene expression were determined with the Kruskal-Wallis test. RESULTS Of 265 genes studied, 11 showed statistically different expression in diseased aorta as compared with control. The following three genes were downregulated in AAA: collagen VI alpha1 (P <.037), glycoprotein IIIA (P <.006), and alpha2-macroglobulin (P <.020). The following two genes were upregulated in AOD: laminin alpha4 (P <.034) and insulin-like growth factor 2 receptor (P <.049). The following three genes were upregulated in both AAA and AOD: matrix metalloproteinase-9 (MMP-9; P <.005), intercellular adhesion molecule-1 (P <.012), and tumor necrosis factor--beta receptor (P <.022). The following three genes were downregulated in both AAA and AOD: integrin alpha5 (P <.012), ephrin A5 (P <.037), and rho/rac guanine nucleotide exchange factor (P <.028). Of 16 MMPs evaluated, only MMP-9 was significantly (P <.005) upregulated in both AAA and AOD. Evaluation results of four tissue inhibitors of metalloproteinases showed no significant difference in expression for all tissue types, although tissue inhibitor of metalloproteinase-1 trended toward upregulation in AAA (P =.053). Eight of the fifteen most highly expressed genes in all the groups were extracellular matrix or secreted proteins. Of these, only collagen VI alpha1 (P <.037) showed a significant change, although biglycan trended toward downregulation in AAA (P =.076). CONCLUSION This study used cDNA array technology in the comparison of human control and pathologic aortic tissue. Six genes had similar differential expression in both AAA and AOD as compared with control. Even more interesting were differences between AAA and AOD in the expression of five genes. These data suggest a similarity in genetic expression for both AAA and AOD, with altered expression of several genes playing a role in disease differentiation.
Collapse
Affiliation(s)
- Peter J Armstrong
- Section of Vascular Surgery, Sigfried and Janet Weis Center for Research, Geisinger Medical Center, Danville, PA 17822-2150, USA
| | | | | | | | | | | | | | | |
Collapse
|
21
|
Orrico A, Galli L, Falciani M, Bracci M, Cavaliere ML, Rinaldi MM, Musacchio A, Sorrentino V. A mutation in the pleckstrin homology (PH) domain of the FGD1 gene in an Italian family with faciogenital dysplasia (Aarskog-Scott syndrome). FEBS Lett 2000; 478:216-20. [PMID: 10930571 DOI: 10.1016/s0014-5793(00)01857-3] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Aarskog-Scott Syndrome (AAS) is an X-linked disorder characterised by short stature and multiple facial, limb and genital abnormalities. A gene, FGD1, altered in a patient with AAS phenotype, has been identified and found to encode a protein with homology to Rho/Rac guanine nucleotide exchange factors (Rho/Rac GEF). However, since this original report on identification of a mutated FGD1 gene in an AAS patient, no additional mutations in the FGD1 gene have been described. We analysed 13 independent patients with clinical diagnosis of AAS. One patient presented a mutation that results in a nucleotide change in exon 10 of the FGD1 gene (G2559>A) substituting a Gln for Arg in position 610. The mutation was found to segregate with the AAS phenotype in affected males and carrier females in the family of this patient. Interestingly, Arg-610 is located within one of the two pleckstrin homology (PH) domains of the FGD1 gene and it corresponds to a highly conserved residue which has been involved in InsP binding in PH domains of other proteins. The same residue is often mutated in the Bruton's tyrosine kinase (Btk) gene in patients with an X-linked agammaglobulinemia. The Arg610Gln mutation represents the first case of a mutation in the PH domain of the FGD1 gene and additional evidence that mutations in PH domains can be associated to human diseases.
Collapse
Affiliation(s)
- A Orrico
- U.O. Genetica Medica, Policlinico 'Le Scotte', Siena, Italy.
| | | | | | | | | | | | | | | |
Collapse
|
22
|
Pasteris NG, Nagata K, Hall A, Gorski JL. Isolation, characterization, and mapping of the mouse Fgd3 gene, a new Faciogenital Dysplasia (FGD1; Aarskog Syndrome) gene homologue. Gene 2000; 242:237-47. [PMID: 10721717 DOI: 10.1016/s0378-1119(99)00518-1] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
FGD1 gene mutations result in faciogenital dysplasia (FGDY, Aarskog syndrome), an X-linked developmental disorder that adversely affects the formation of multiple skeletal structures. FGD1 encodes a guanine nucleotide exchange factor (GEF) that specifically activates the Rho GTPase Cdc42. By way of Cdc42, FGD1 regulates the actin cytoskeleton and activates the c-Jun N-terminal kinase signaling cascade to regulate cell growth and differentiation. Previous work shows that FGD1 is the founding member of a family of related genes including the mouse Fgd2 gene and the rat Frabin gene. Here, we report on the isolation, characterization, and mapping of the mouse Fgd3 gene, a new and novel member of the FGD1 gene family. Fgd3 cDNA encodes a 733-amino-acid protein with a predicted mass of 81 kDa. Fgd3 and FGD1 share a high degree of sequence identity that spans >560 contiguous amino acid residues. Like FGD1, Fgd3 contains adjacent RhoGEF and pleckstrin homology (PH) domains, a second carboxy-terminal PH domain, and a distinctive FYVE domain. Together, these domains appear to form a canonical core structure for FGD1 family members. In addition, compared to other FGD1 family members, Fgd3 contains different structural regions that may be involved in distinct signaling interactions. Microinjection studies show that Fgd3 stimulates fibroblasts to form filopodia, actin microspikes formed upon the stimulation of Cdc42. Fgd3 transcripts are present in several diverse tissues and during mouse embryogenesis, suggesting a developmentally regulated pattern of expression and a potential role in embryonic development. Genetic linkage and radiation hybrid mapping data show that Fgd3 and the human FGD3 ortholog map to syntenic regions of murine chromosome 13 and human chromosome 9q22, respectively. We conclude that Fgd3 is a new and novel member of the FGD1 family of RhoGEF proteins.
Collapse
MESH Headings
- 3T3 Cells
- Abnormalities, Multiple/genetics
- Amino Acid Sequence
- Animals
- Base Sequence
- Blotting, Northern
- Chromosomes/genetics
- Chromosomes, Human, Pair 9/genetics
- DNA, Complementary/chemistry
- DNA, Complementary/genetics
- DNA, Complementary/isolation & purification
- Facial Bones/abnormalities
- Gene Expression Regulation, Developmental
- Guanine Nucleotide Exchange Factors/genetics
- Guanine Nucleotide Exchange Factors/physiology
- Humans
- Male
- Mice
- Mice, Inbred C57BL
- Molecular Sequence Data
- Muridae
- Proteins/genetics
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Rho Guanine Nucleotide Exchange Factors
- Sequence Alignment
- Sequence Analysis, DNA
- Sequence Homology, Amino Acid
- Tissue Distribution
- Urogenital Abnormalities/genetics
- cdc42 GTP-Binding Protein/metabolism
Collapse
Affiliation(s)
- N G Pasteris
- Department of Pediatrics, University of Michigan Medical School, Ann Arbor 48109-0688, USA
| | | | | | | |
Collapse
|
23
|
Pasteris NG, Gorski JL. Isolation, characterization, and mapping of the mouse and human Fgd2 genes, faciogenital dysplasia (FGD1; Aarskog syndrome) gene homologues. Genomics 1999; 60:57-66. [PMID: 10458911 DOI: 10.1006/geno.1999.5903] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
FGD1 encodes a guanine nucleotide exchange factor (GEF) that specifically activates the Rho GTPase Cdc42. FGD1 gene mutations result in faciogenital dysplasia (FGDY, Aarskog syndrome), an X-linked developmental disorder that adversely affects the formation of multiple skeletal structures. Database searches show that the Caenorhabditis elegans genome contains an FGD1 homologue. Since C. elegans genes often have multiple vertebrate homologues, we hypothesized the existence of multiple mammalian FGD1-related sequences. Here we report the use of degenerate PCR to isolate and characterize the mouse and human Fgd2 genes, new members of the FGD1 gene family. Fgd2 cDNA encodes a 727-amino-acid protein with a predicted mass of 82 kDa. Fgd2 and FGD1 share a high degree of sequence identity that spans >560 contiguous amino acid residues. Fgd2, like FGD1, contains adjacent RhoGEF and PH domains, a second carboxy-terminal PH domain, and a distinctive FYVE domain. Genomic PCR studies indicate some degree of conserved gene structure between Fgd2 and FGD1. Fgd2 transcripts are present in several diverse tissues and during mouse embryogenesis, suggesting a role in embryonic development. Genetic linkage and radiation hybrid mapping data show that Fgd2 and the human FGD2 ortholog map to syntenic regions of murine chromosome 17 and human chromosome 6p21.2, respectively. The observation that all FGD1 gene family members contain equivalent signaling domains and a conserved structural organization strongly suggests that these signaling domains form a canonical core structure for members of the FGD1 family of RhoGEF proteins.
Collapse
MESH Headings
- Abnormalities, Multiple/genetics
- Amino Acid Sequence
- Animals
- Base Sequence
- Blotting, Northern
- Chromosome Mapping
- Chromosomes/genetics
- Chromosomes, Human, Pair 6/genetics
- Cloning, Molecular
- DNA Primers
- DNA, Complementary/chemistry
- DNA, Complementary/genetics
- DNA, Complementary/isolation & purification
- Facial Bones/abnormalities
- Facial Bones/metabolism
- GTP-Binding Proteins/genetics
- Guanine Nucleotide Exchange Factors
- Humans
- Mice
- Mice, Inbred C57BL
- Mice, Inbred Strains
- Molecular Sequence Data
- Muridae
- Polymerase Chain Reaction
- Proteins/genetics
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Sequence Alignment
- Sequence Analysis, DNA
- Sequence Homology, Amino Acid
- Tissue Distribution
- Urogenital Abnormalities/genetics
Collapse
Affiliation(s)
- N G Pasteris
- Department of Human Genetics, University of Michigan Medical Center, Ann Arbor, Michigan, 48109-0688, USA
| | | |
Collapse
|
24
|
Abstract
Cdc42p is an essential GTPase that belongs to the Rho/Rac subfamily of Ras-like GTPases. These proteins act as molecular switches by responding to exogenous and/or endogenous signals and relaying those signals to activate downstream components of a biological pathway. The 11 current members of the Cdc42p family display between 75 and 100% amino acid identity and are functional as well as structural homologs. Cdc42p transduces signals to the actin cytoskeleton to initiate and maintain polarized gorwth and to mitogen-activated protein morphogenesis. In the budding yeast Saccharomyces cerevisiae, Cdc42p plays an important role in multiple actin-dependent morphogenetic events such as bud emergence, mating-projection formation, and pseudohyphal growth. In mammalian cells, Cdc42p regulates a variety of actin-dependent events and induces the JNK/SAPK protein kinase cascade, which leads to the activation of transcription factors within the nucleus. Cdc42p mediates these processes through interactions with a myriad of downstream effectors, whose number and regulation we are just starting to understand. In addition, Cdc42p has been implicated in a number of human diseases through interactions with its regulators and downstream effectors. While much is known about Cdc42p structure and functional interactions, little is known about the mechanism(s) by which it transduces signals within the cell. Future research should focus on this question as well as on the detailed analysis of the interactions of Cdc42p with its regulators and downstream effectors.
Collapse
Affiliation(s)
- D I Johnson
- Department of Microbiology & Molecular Genetics and the Markey Center for Molecular Genetics, University of Vermont, Burlington, Vermont 05405,
| |
Collapse
|
25
|
Whitehead IP, Abe K, Gorski JL, Der CJ. CDC42 and FGD1 cause distinct signaling and transforming activities. Mol Cell Biol 1998; 18:4689-97. [PMID: 9671479 PMCID: PMC109055 DOI: 10.1128/mcb.18.8.4689] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/1998] [Accepted: 05/29/1998] [Indexed: 02/08/2023] Open
Abstract
Activated forms of different Rho family members (CDC42, Rac1, RhoA, RhoB, and RhoG) have been shown to transform NIH 3T3 cells as well as contribute to Ras transformation. Rho family guanine nucleotide exchange factors (GEFs) (also known as Dbl family proteins) that activate CDC42, Rac1, and RhoA also demonstrate oncogenic potential. The faciogenital dysplasia gene product, FGD1, is a Dbl family member that has recently been shown to function as a CDC42-specific GEF. Mutations within the FGD1 locus cosegregate with faciogenital dysplasia, a multisystemic disorder resulting in extensive growth impairments throughout the skeletal and urogenital systems. Here we demonstrate that FGD1 expression is sufficient to cause tumorigenic transformation of NIH 3T3 fibroblasts. Although both FGD1 and constitutively activated CDC42 cooperated with Raf and showed synergistic focus-forming activity, both quantitative and qualitative differences in their functions were seen. FGD1 and CDC42 also activated common nuclear signaling pathways. However, whereas both showed comparable activation of c-Jun, CDC42 showed stronger activation of serum response factor and FGD1 was consistently a better activator of Elk-1. Although coexpression of FGD1 with specific inhibitors of CDC42 function demonstrated the dependence of FGD1 signaling activity on CDC42 function, FGD1 signaling activities were not always consistent with the direct or exclusive stimulation of CDC42 function. In summary, FGD1 and CDC42 signaling and transformation are distinct, thus suggesting that FGD1 may be mediating some of its biological activities through non-CDC42 targets.
Collapse
Affiliation(s)
- I P Whitehead
- Department of Pharmacology and Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599-7295, USA
| | | | | | | |
Collapse
|