RESUMEN
Germline histone H3.3 amino acid substitutions, including H3.3G34R/V, cause severe neurodevelopmental syndromes. To understand how these mutations impact brain development, we generated H3.3G34R/V/W knock-in mice and identified strikingly distinct developmental defects for each mutation. H3.3G34R-mutants exhibited progressive microcephaly and neurodegeneration, with abnormal accumulation of disease-associated microglia and concurrent neuronal depletion. G34R severely decreased H3K36me2 on the mutant H3.3 tail, impairing recruitment of DNA methyltransferase DNMT3A and its redistribution on chromatin. These changes were concurrent with sustained expression of complement and other innate immune genes possibly through loss of non-CG (CH) methylation and silencing of neuronal gene promoters through aberrant CG methylation. Complement expression in G34R brains may lead to neuroinflammation possibly accounting for progressive neurodegeneration. Our study reveals that H3.3G34-substitutions have differential impact on the epigenome, which underlie the diverse phenotypes observed, and uncovers potential roles for H3K36me2 and DNMT3A-dependent CH-methylation in modulating synaptic pruning and neuroinflammation in post-natal brains.
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ADN Metiltransferasa 3A , Histonas , Animales , Ratones , ADN (Citosina-5-)-Metiltransferasas/genética , Metilación de ADN/genética , Metilasas de Modificación del ADN/genética , Histonas/metabolismo , Enfermedades NeuroinflamatoriasRESUMEN
Splicing and endoplasmic reticulum (ER)-proteostasis are two key processes that ultimately regulate the functional proteins that are produced by a cell. However, the extent to which these processes interact remains poorly understood. Here, we identify SNRPB and other components of the Sm-ring, as targets of the unfolded protein response and novel regulators of export from the ER. Mechanistically, The Sm-ring regulates the splicing of components of the ER export machinery, including Sec16A, a component of ER exit sites. Loss of function of SNRPB is causally linked to cerebro-costo-mandibular syndrome (CCMS), a genetic disease characterized by bone defects. We show that heterozygous deletion of SNRPB in mice resulted in bone defects reminiscent of CCMS and that knockdown of SNRPB delays the trafficking of type-I collagen. Silencing SNRPB inhibited osteogenesis in vitro, which could be rescued by overexpression of Sec16A. This rescue indicates that the role of SNRPB in osteogenesis is linked to its effects on ER-export. Finally, we show that SNRPB is a target for the unfolded protein response, which supports a mechanistic link between the spliceosome and ER-proteostasis. Our work highlights components of the Sm-ring as a novel node in the proteostasis network, shedding light on CCMS pathophysiology.
RESUMEN
Hedgehog (HH) signaling is important for embryonic pattering and stem cell differentiation. The G protein-coupled receptor (GPCR) Smoothened (SMO) is the key HH signal transducer modulating both transcription-dependent and transcription-independent responses. We show that SMO protects naive mouse embryonic stem cells (ESCs) from dissociation-induced cell death. We exploited this SMO dependency to perform a genetic screen in haploid ESCs where we identify the Golgi proteins TMED2 and TMED10 as factors for SMO regulation. Super-resolution microscopy shows that SMO is normally retained in the endoplasmic reticulum (ER) and Golgi compartments, and we demonstrate that TMED2 binds to SMO, preventing localization to the plasma membrane. Mutation of TMED2 allows SMO accumulation at the plasma membrane, recapitulating early events after HH stimulation. We demonstrate the physiologic relevance of this interaction in neural differentiation, where TMED2 functions to repress HH signal strength. Identification of TMED2 as a binder and upstream regulator of SMO opens the way for unraveling the events in the ER-Golgi leading to HH signaling activation.
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Proteínas Hedgehog , Receptores Acoplados a Proteínas G , Animales , Membrana Celular/metabolismo , Retículo Endoplásmico/metabolismo , Proteínas Hedgehog/genética , Proteínas Hedgehog/metabolismo , Proteínas de la Membrana , Ratones , Receptores Acoplados a Proteínas G/genética , Receptores Acoplados a Proteínas G/metabolismo , Transducción de Señal/genética , Receptor Smoothened/genética , Receptor Smoothened/metabolismo , Proteínas de Transporte VesicularRESUMEN
Fibroblast Growth Factor 6 (FGF6), also referred to as HST2 or HBGF6, is a member of the Fibroblast Growth Factor (FGF), the Heparin Binding Growth Factor (HBGF) and the Heparin Binding Secretory Transforming Gene (HST) families. The genomic and protein structure of FGF6 is highly conserved among varied species, as is its expression in muscle and muscle progenitor cells. Like other members of the FGF family, FGF6 regulates cell proliferation, differentiation, and migration. Specifically, it plays key roles in myogenesis and muscular regeneration, angiogenesis, along with iron transport and lipid metabolism. Similar to others from the FGF family, FGF6 also possesses oncogenic transforming activity, and as such is implicated in a variety of cancers.
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Diferenciación Celular , Factor 6 de Crecimiento de Fibroblastos , Humanos , Animales , Diferenciación Celular/genética , Factor 6 de Crecimiento de Fibroblastos/genética , Factor 6 de Crecimiento de Fibroblastos/metabolismo , Desarrollo de Músculos/genética , Proliferación Celular/genética , Neoplasias/genética , Neoplasias/metabolismo , Neoplasias/patología , Movimiento Celular/genéticaRESUMEN
SF3B proteins form a heptameric complex in the U2 small nuclear ribonucleoprotein, essential for pre-mRNA splicing. Heterozygous pathogenic variants in human SF3B4 are associated with head, face, limb, and vertebrae defects. Using the CRISPR/Cas9 system, we generated mice with constitutive heterozygous deletion of Sf3b4 and showed that mutant embryos have abnormal vertebral development. Vertebrae abnormalities were accompanied by changes in levels and expression pattern of Hox genes in the somites. RNA sequencing analysis of whole embryos and somites of Sf3b4 mutant and control litter mates revealed increased expression of other Sf3b4 genes. However, the mutants exhibited few differentially expressed genes and a large number of transcripts with differential splicing events (DSE), predominantly increased exon skipping and intron retention. Transcripts with increased DSE included several genes involved in chromatin remodeling that are known to regulate Hox expression. Our study confirms that Sf3b4 is required for normal vertebrae development and shows, for the first time, that like Sf3b1, Sf3b4 also regulates Hox expression. We propose that abnormal splicing of chromatin remodelers is primarily responsible for vertebral defects found in Sf3b4 heterozygous mutant embryos.
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Cromatina , Empalme del ARN , Humanos , Animales , Ratones , Factores de Empalme de ARN/genética , Factores de Empalme de ARN/metabolismo , Empalme del ARN/genética , Factores de Transcripción/genética , Genes HomeoboxRESUMEN
EFTUD2 is mutated in patients with mandibulofacial dysostosis with microcephaly (MFDM). We generated a mutant mouse line with conditional mutation in Eftud2 and used Wnt1-Cre2 to delete it in neural crest cells. Homozygous deletion of Eftud2 causes brain and craniofacial malformations, affecting the same precursors as in MFDM patients. RNAseq analysis of embryonic heads revealed a significant increase in exon skipping and increased levels of an alternatively spliced Mdm2 transcript lacking exon 3. Exon skipping in Mdm2 was also increased in O9-1 mouse neural crest cells after siRNA knock-down of Eftud2 and in MFDM patient cells. Moreover, we found increased nuclear P53, higher expression of P53-target genes and increased cell death. Finally, overactivation of the P53 pathway in Eftud2 knockdown cells was attenuated by overexpression of non-spliced Mdm2, and craniofacial development was improved when Eftud2-mutant embryos were treated with Pifithrin-α, an inhibitor of P53. Thus, our work indicates that the P53-pathway can be targeted to prevent craniofacial abnormalities and shows a previously unknown role for alternative splicing of Mdm2 in the etiology of MFDM.
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Ribonucleoproteína Nuclear Pequeña U5 , Proteína p53 Supresora de Tumor , Animales , Homocigoto , Humanos , Ratones , Mutación , Factores de Elongación de Péptidos/genética , Proteínas Proto-Oncogénicas c-mdm2/genética , Proteínas Proto-Oncogénicas c-mdm2/metabolismo , Ribonucleoproteína Nuclear Pequeña U5/genética , Eliminación de Secuencia , Proteína p53 Supresora de Tumor/genética , Proteína p53 Supresora de Tumor/metabolismoRESUMEN
Embryos with homozygous mutation of Eftud2 in their neural crest cells (Eftud2ncc-/-) have brain and craniofacial malformations, hyperactivation of the P53-pathway and die before birth. Treatment of Eftud2ncc-/- embryos with pifithrin-α, a P53-inhibitor, partly improved brain and craniofacial development. To uncover if craniofacial malformations and death were indeed due to P53 hyperactivation we generated embryos with homozygous loss of function mutations in both Eftud2 and Trp53 in the neural crest cells. We evaluated the molecular mechanism underlying craniofacial development in pifithrin-α-treated embryos and in Eftud2; Trp53 double homozygous (Eftud2ncc-/-; Trp53ncc-/-) mutant embryos. Eftud2ncc-/- embryos that were treated with pifithrin-α or homozygous mutant for Trp53 in their neural crest cells showed reduced apoptosis in their neural tube and reduced P53-target activity. Furthermore, although the number of SOX10 positive cranial neural crest cells was increased in embryonic day (E) 9.0 Eftud2ncc-/-; Trp53ncc-/- embryos compared to Eftud2ncc-/- mutants, brain and craniofacial development, and survival were not improved in double mutant embryos. Furthermore, mis-splicing of both P53-regulated transcripts, Mdm2 and Foxm1, and a P53-independent transcript, Synj2bp, was increased in the head of Eftud2ncc-/-; Trp53ncc-/- embryos. While levels of Zmat3, a P53- regulated splicing factor, was similar to those of wild-type. Altogether, our data indicate that both P53-regulated and P53-independent pathways contribute to craniofacial malformations and death of Eftud2ncc-/- embryos.
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Anomalías Craneofaciales , Cresta Neural , Factores de Elongación de Péptidos , Ribonucleoproteína Nuclear Pequeña U5 , Animales , Anomalías Craneofaciales/genética , Anomalías Craneofaciales/metabolismo , Eliminación de Gen , Homocigoto , Cresta Neural/metabolismo , Factores de Elongación de Péptidos/metabolismo , Ribonucleoproteína Nuclear Pequeña U5/genética , Ribonucleoproteína Nuclear Pequeña U5/metabolismo , Proteína p53 Supresora de Tumor/genéticaRESUMEN
TMED2, a member of the transmembrane emp24 domain (TMED) family, is required for transport of cargo proteins between the ER and Golgi. TMED2 is also important for normal morphogenesis of mouse embryos and their associated placenta, and in fact Tmed2 homozygous mutant embryos arrest at mid-gestation due to a failure of placental labyrinth layer formation. Differentiation of the placental labyrinth layer depends on chorioallantoic attachment (contact between the chorion and allantois), and branching morphogenesis (mingling of cells from these two tissues). Since Tmed2 mRNA was found in both the chorion and allantois, and 50% of Tmed2 homozygous mutant embryos failed to undergo chorioallantoic attachment, the tissue-specific requirement of Tmed2 during placental labyrinth layer formation remained a mystery. Herein, we report differential localization of TMED2 protein in the chorion and allantois, abnormal ER retention of Fibronectin in Tmed2 homozygous mutant allantoises and cell-autonomous requirement for Tmed2 in the chorion for chorioallantoic attachment and fusion. Using an ex vivo model of explanted chorions and allantoises, we showed that chorioallantoic attachment failed to occur in 50% of samples when homozygous mutant chorions were recombined with wild type allantoises. Furthermore, though expression of genes associated with trophoblast differentiation was maintained in Tmed2 mutant chorions with chorioallantoic attachment, expression of these genes was attenuated. In addition, Tmed2 homozygous mutant allantoises could undergo branching morphogenesis, however the region of mixing between mutant and wild type cells was reduced, and expression of genes associated with trophoblast differentiation was also attenuated. Our data also suggest that Fibronectin is a cargo protein of TMED2 and indicates that Tmed2 is required cell-autonomously and non-autonomously in the chorion and the allantois for placental labyrinth layer formation.
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Alantoides/metabolismo , Corion/metabolismo , Proteínas de Transporte Vesicular/metabolismo , Animales , Diferenciación Celular/fisiología , Retículo Endoplásmico/metabolismo , Femenino , Fibronectinas/metabolismo , Regulación del Desarrollo de la Expresión Génica/genética , Masculino , Proteínas de la Membrana , Ratones , Ratones Endogámicos C57BL , Morfogénesis/fisiología , Placenta/metabolismo , Embarazo , Ratas , TrofoblastosRESUMEN
Regulated transport through the secretory pathway is essential for embryonic development and homeostasis. Disruptions in this process impact cell fate, differentiation and survival, often resulting in abnormalities in morphogenesis and in disease. Several congenital malformations are caused by mutations in genes coding for proteins that regulate cargo protein transport in the secretory pathway. The severity of mutant phenotypes and the unclear aetiology of transport protein-associated pathologies have motivated research on the regulation and mechanisms through which these proteins contribute to morphogenesis. This review focuses on the role of the p24/transmembrane emp24 domain (TMED) family of cargo receptors in development and disease.
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Proteínas de Transporte Vesicular/metabolismo , Proteínas de Transporte Vesicular/fisiología , Animales , Proteínas Portadoras/metabolismo , Humanos , Membranas Intracelulares/metabolismo , Membranas Intracelulares/fisiología , Proteínas de la Membrana/genética , Transporte de Proteínas/genética , Transporte de Proteínas/fisiología , Vesículas Transportadoras/metabolismo , Vesículas Transportadoras/fisiología , Proteínas de Transporte Vesicular/genéticaRESUMEN
Background: Suboptimal folate intake, a risk factor for birth defects, is common even in areas with folate fortification. A polymorphism in methylenetetrahydrofolate dehydrogenase 1 (MTHFD1), R653Q (MTHFD1 c.1958 G > A), has also been associated with increased birth defect risk, likely through reduced purine synthesis. Objective: We aimed to determine if the interaction of MTHFD1 synthetase deficiency and low folate intake increases developmental abnormalities in a mouse model for MTHFD1 R653Q. Methods: Female Mthfd1S+/+ and Mthfd1S+/- mice were fed control or low-folate diets (2 and 0.3 mg folic acid/kg diet, respectively) before mating and during pregnancy. Embryos and placentas were examined for anomalies at embryonic day 10.5. Maternal 1-carbon metabolites were measured in plasma and liver. Results: Delays and defects doubled in litters of Mthfd1S+/- females fed low-folate diets compared to wild-type females fed either diet, or Mthfd1S+/- females fed control diets [P values (defects): diet 0.003, maternal genotype 0.012, diet × maternal genotype 0.014]. These adverse outcomes were associated with placental dysmorphology. Intrauterine growth restriction was increased by embryonic Mthfd1S+/- genotype, folate deficiency, and interaction of maternal Mthfd1S+/- genotype with folate deficiency (P values: embryonic genotype 0.045, diet 0.0081, diet × maternal genotype 0.0019). Despite a 50% increase in methylenetetrahydrofolate reductase expression in low-folate maternal liver (P diet = 0.0007), methyltetrahydrofolate concentration decreased 70% (P diet <0.0001) and homocysteine concentration doubled in plasma (P diet = 0.0001); S-adenosylmethionine decreased 40% and S-adenosylhomocysteine increased 20% in low-folate maternal liver (P diet = 0.002 and 0.0002, respectively). Conclusions: MTHFD1 synthetase-deficient mice are more sensitive to low folate intake than wild-type mice during pregnancy. Reduced purine synthesis due to synthetase deficiency and altered methylation potential due to low folate may increase pregnancy complications. Further studies and individualized intake recommendations may be required for women homozygous for the MTHFD1 R653Q variant.
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Anomalías Congénitas/etiología , Deficiencia de Ácido Fólico/complicaciones , Ácido Fólico/administración & dosificación , Formiato-Tetrahidrofolato Ligasa/deficiencia , Genotipo , Meteniltetrahidrofolato Ciclohidrolasa/deficiencia , Metilenotetrahidrofolato Deshidrogenasa (NADP)/deficiencia , Enzimas Multifuncionales/deficiencia , Polimorfismo Genético , Complicaciones del Embarazo/etiología , Animales , Metilación de ADN , Dieta , Modelos Animales de Enfermedad , Femenino , Desarrollo Fetal , Retardo del Crecimiento Fetal/etiología , Ácido Fólico/sangre , Deficiencia de Ácido Fólico/sangre , Deficiencia de Ácido Fólico/genética , Deficiencia de Ácido Fólico/metabolismo , Formiato-Tetrahidrofolato Ligasa/genética , Formiato-Tetrahidrofolato Ligasa/metabolismo , Ligasas , Hígado/metabolismo , Meteniltetrahidrofolato Ciclohidrolasa/genética , Meteniltetrahidrofolato Ciclohidrolasa/metabolismo , Metilenotetrahidrofolato Deshidrogenasa (NADP)/genética , Metilenotetrahidrofolato Deshidrogenasa (NADP)/metabolismo , Metilenotetrahidrofolato Reductasa (NADPH2)/metabolismo , Ratones , Enzimas Multifuncionales/genética , Enzimas Multifuncionales/metabolismo , Placenta , Embarazo , Complicaciones del Embarazo/sangre , Complicaciones del Embarazo/genética , Complicaciones del Embarazo/metabolismo , Preñez , S-Adenosilhomocisteína/metabolismo , S-Adenosilmetionina/metabolismo , Tetrahidrofolatos/sangreRESUMEN
Marden-Walker syndrome is challenging to diagnose, as there is significant overlap with other multi-system congenital contracture syndromes including Beals congenital contractural arachnodactyly, D4ST1-Deficient Ehlers-Danlos syndrome (adducted thumb-clubfoot syndrome), Schwartz-Jampel syndrome, Freeman-Sheldon syndrome, Cerebro-oculo-facio-skeletal syndrome, and Van den Ende-Gupta syndrome. We discuss this differential diagnosis in the context of a boy from a consanguineous union with Van den Ende-Gupta syndrome, a diagnosis initially confused by the atypical presence of intellectual disability. SNP microarray and whole exome sequencing identified a homozygous frameshift mutation (p.L870V) in SCARF2 and predicted damaging mutations in several genes, most notably DGCR2 (p.P75L) and NCAM2 (p.S147G), both possible candidates for this child's intellectual disability. We review distinguishing features for each Marden-Walker-like syndrome and propose a clinical algorithm for diagnosis among this spectrum of disorders. © 2016 Wiley Periodicals, Inc.
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Anomalías Múltiples/diagnóstico , Anomalías Múltiples/genética , Aracnodactilia/diagnóstico , Aracnodactilia/genética , Blefarofimosis/diagnóstico , Blefarofimosis/genética , Contractura/diagnóstico , Contractura/genética , Estudios de Asociación Genética , Anomalías Múltiples/metabolismo , Aracnodactilia/metabolismo , Blefarofimosis/metabolismo , Niño , Contractura/metabolismo , Variaciones en el Número de Copia de ADN , Exoma , Mutación del Sistema de Lectura , Secuenciación de Nucleótidos de Alto Rendimiento , Homocigoto , Humanos , Masculino , Imagen Multimodal , Análisis de Secuencia por Matrices de Oligonucleótidos , Fenotipo , Polimorfismo de Nucleótido Simple , Receptores Depuradores de Clase F/genéticaRESUMEN
BACKGROUND: A single nucleotide polymorphism (SNP) in the synthetase domain of the trifunctional folate-dependent enzyme MTHFD1 (c.1958G>A, R653Q) has been linked to adverse pregnancy outcomes, neural tube defects, and possibly congenital heart defects. Maternal folate deficiency may also modify the risk associated with these disorders. We recently established a mouse model with a mild deficiency of 10-formyltetrahydrofolate synthetase activity in MTHFD1 (Mthfd1S(+/-) mice) to investigate disorders associated with SNPs in this gene. The effect of synthetase deficiency on embryonic heart development has not yet been examined. METHODS: Female Mthfd1S(+/+) and (+/-) mice were placed on control and folate-deficient diets for 6 weeks before mating to Mthfd1S(+/-) males. Embryos and placentae were collected at embryonic day 14.5. Embryos were evaluated for congenital heart defects by histological examination. RESULTS: Embryonic Mthfd1S(+/-) genotype was associated with an increased incidence of heart defects, primarily ventricular septal defects. Other markers of embryonic development (crown-rump length, embryonic weight, embryonic delay, placental weight, and thickness of the ventricular myocardium) were not affected by embryonic genotype. Maternal genotype and diet did not have a significant effect on these outcomes. CONCLUSION: Deficiency of the MTHFD1 10-formyltetrahydrofolate synthetase activity in embryos is associated with increased incidence of congenital heart defects.
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Aminohidrolasas/genética , Modelos Animales de Enfermedad , Formiato-Tetrahidrofolato Ligasa/genética , Cardiopatías Congénitas/genética , Metilenotetrahidrofolato Deshidrogenasa (NADP)/genética , Complejos Multienzimáticos/genética , Animales , Femenino , Masculino , Ratones , Ratones Endogámicos BALB C , Ratones NoqueadosRESUMEN
Patients with mutations in MMACHC have the autosomal recessive disease of cobalamin metabolism known as cblC. These patients are unable to convert cobalamin into the two active forms, methylcobalamin and adenosylcobalamin and consequently have elevated homocysteine and methylmalonic acid in blood and urine. In addition, some cblC patients have structural abnormalities, including congenital heart defects. MMACHC is conserved in the mouse and shows tissue and stage-specific expression pattern in midgestation stage embryos. To create a mouse model of cblC we generated a line of mice with a gene-trap insertion in intron 1 of the Mmachc gene, (Mmachc(Gt(AZ0348)Wtsi)). Heterozygous mice show a 50% reduction of MMACHC protein, and have significantly higher levels of homocysteine and methylmalonic acid in their blood. The Mmachc(Gt) allele was inherited with a transmission ratio distortion in matings with heterozygous animals. Furthermore, homozygous Mmachc(Gt) embryos were not found after embryonic day 3.5 and these embryos were unable to generate giant cells in outgrowth assays. Our findings confirm that cblC is modeled in mice with reduced levels of Mmachc and suggest an early requirement for Mmachc in mouse development.
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Proteínas Portadoras/genética , Desarrollo Embrionario/genética , Alelos , Errores Innatos del Metabolismo de los Aminoácidos/genética , Animales , Femenino , Orden Génico , Marcación de Gen , Vectores Genéticos/genética , Genotipo , Hiperhomocisteinemia/genética , Masculino , Ratones , Oxidorreductasas , FenotipoRESUMEN
BACKGROUND: 22q11.2 deletion syndrome (22q11.2DS) is the most common microdeletion disorder, affecting an estimated 1 : 2000-4000 live births. Patients with 22q11.2DS have a broad spectrum of phenotypic abnormalities which generally includes congenital cardiac abnormalities, palatal anomalies, and immunodeficiency. Additional findings, such as skeletal anomalies and autoimmune disorders, can confer significant morbidity in a subset of patients. 22q11.2DS is a contiguous gene DS and over 40 genes are deleted in patients; thus deletion of several genes within this region contributes to the clinical features. Mutations outside or on the remaining 22q11.2 allele are also known to modify the phenotype. METHODS: We utilised whole exome, targeted exome and/or Sanger sequencing to examine the genome of 17 patients with 22q11.2 deletions and phenotypic features found in <10% of affected individuals. RESULTS AND CONCLUSIONS: In four unrelated patients, we identified three novel mutations in SNAP29, the gene implicated in the autosomal recessive condition cerebral dysgenesis, neuropathy, ichthyosis and keratoderma (CEDNIK). SNAP29 maps to 22q11.2 and encodes a soluble SNARE protein that is predicted to mediate vesicle fusion at the endoplasmic reticulum or Golgi membranes. This work confirms that the phenotypic variability observed in a subset of patients with 22q11.2DS is due to mutations on the non-deleted chromosome, which leads to unmasking of autosomal recessive conditions such as CEDNIK, Kousseff, and a potentially autosomal recessive form of Opitz G/BBB syndrome. Furthermore, our work implicates SNAP29 as a major modifier of variable expressivity in 22q11.2 DS patients.
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Síndrome de DiGeorge/genética , Mutación/genética , Proteínas Qb-SNARE/genética , Proteínas Qc-SNARE/genética , Mapeo Cromosómico , Estudios de Cohortes , Síndrome de DiGeorge/patología , Exoma , Femenino , Humanos , Masculino , Fenotipo , Análisis de Secuencia de ADNRESUMEN
BACKGROUND: Development of a mature organism from a single cell requires a series of important morphological changes, which is in part regulated by alternative splicing. In this article, we report the expression of Esrp1 during early mouse embryogenesis, a splicing factor implicated in epithelial to mesenchymal transitions. RESULTS: By qRT-PCR, we find higher expression of Esrp1 and Esrp2 in placenta compared to the embryos. We also find a correlation between the expression of Esrp1 and alternative splicing of several known target exons. Using in situ RNA hybridization we show that while Esrp1 expression is ubiquitous in embryonic day (E)6.5 mouse embryos, expression becomes restricted to the chorion and definitive endoderm starting at E7.5. Esrp1 expression was consistently restricted to a subset of epithelial cell types in developing embryos from E9.5 to E13.5. CONCLUSIONS: Our results suggest that Esrp1 could play an important role in the morphological changes underlying embryogenesis of the placenta and embryo.
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Embrión de Mamíferos/metabolismo , Desarrollo Embrionario/fisiología , Células Epiteliales/metabolismo , Regulación del Desarrollo de la Expresión Génica/fisiología , Empalme del ARN/fisiología , Proteínas de Unión al ARN/biosíntesis , Animales , Embrión de Mamíferos/citología , Células Epiteliales/citología , Femenino , Humanos , Ratones , Especificidad de Órganos/fisiología , Placenta/citología , Placenta/metabolismo , EmbarazoRESUMEN
Van Den Ende-Gupta syndrome (VDEGS) is an extremely rare autosomal-recessive disorder characterized by distinctive craniofacial features, which include blepharophimosis, malar and/or maxillary hypoplasia, a narrow and beaked nose, and an everted lower lip. Other features are arachnodactyly, camptodactyly, peculiar skeletal abnormalities, and normal development and intelligence. We present molecular data on four VDEGS patients from three consanguineous Qatari families belonging to the same highly inbred Bedouin tribe. The patients were genotyped with SNP microarrays, and a 2.4 Mb homozygous region was found on chromosome 22q11 in an area overlapping the DiGeorge critical region. This region contained 44 genes, including SCARF2, a gene that is expressed during development in a number of mouse tissues relevant to the symptoms described above. Sanger sequencing identified a missense change, c.773G>A (p.C258Y), in exon 4 in the two closely related patients and a 2 bp deletion in exon 8, c.1328_1329delTG (p.V443DfsX83), in two unrelated individuals. In parallel with the candidate gene approach, complete exome sequencing was used to confirm that SCARF2 was the gene responsible for VDEGS. SCARF2 contains putative epidermal growth factor-like domains in its extracellular domain, along with a number of positively charged residues in its intracellular domain, indicating that it may be involved in intracellular signaling. However, the function of SCARF2 has not been characterized, and this study reports that phenotypic effects can be associated with defects in the scavenger receptor F family of genes.
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Anomalías Múltiples/genética , Blefarofimosis/genética , Cromosomas Humanos Par 22/genética , Etnicidad/genética , Anomalías Musculoesqueléticas/genética , Receptores Depuradores de Clase F/genética , Secuencia de Aminoácidos , Secuencia de Bases , Femenino , Genes Recesivos , Genotipo , Humanos , Masculino , Análisis por Micromatrices , Datos de Secuencia Molecular , Mutación Missense/genética , Linaje , Polimorfismo de Nucleótido Simple/genética , Qatar , Receptores Depuradores de Clase F/metabolismo , Análisis de Secuencia de ADN , SíndromeRESUMEN
Organ-specific birth defects are seen in patients with some inborn errors of vitamin B(12) metabolism. To determine whether three mouse genes, whose human counterparts are associated with isolated methylmalonic aciduria (Mmaa, Mmab and Mut), show tissue-specific expression during organogenesis, we used in situ hybridization to characterize their pattern of expression in wild type embryos and placentas at embryonic days (E) E10.5, E11.5 and E12.5. These three genes are ubiquitously expressed in the placenta and in embryos at E10.5. At E11.5, we observed tissue specific expression patterns for these three genes in lung, head and Rathke's pouch. At E12.5, although Mut expression was ubiquitous, we found cell-type specific expression patterns for Mmaa and Mmab in the developing craniofacial region, the lung, the liver, and the gut. These results suggest that during organogenesis the proteins encoded by these three genes may interact in only a subset of cells.
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Transferasas Alquil y Aril/genética , Metilmalonil-CoA Mutasa/genética , Proteínas de Transporte de Membrana Mitocondrial/genética , Organogénesis/genética , Placenta/metabolismo , Transferasas Alquil y Aril/metabolismo , Errores Innatos del Metabolismo de los Aminoácidos/genética , Errores Innatos del Metabolismo de los Aminoácidos/metabolismo , Animales , Embrión de Mamíferos , Femenino , Expresión Génica , Humanos , Hibridación in Situ , Mucosa Intestinal/metabolismo , Intestinos/crecimiento & desarrollo , Hígado/crecimiento & desarrollo , Hígado/metabolismo , Pulmón/crecimiento & desarrollo , Pulmón/metabolismo , Metilmalonil-CoA Mutasa/metabolismo , Ratones , Proteínas de Transporte de Membrana Mitocondrial/metabolismo , Miocardio/metabolismo , Especificidad de Órganos , Embarazo , Vitamina B 12/metabolismoRESUMEN
As organizations that facilitate collaboration and communication, scientific societies have an opportunity, and a responsibility, to drive inclusion, diversity, equity, and accessibility in science in academia. The American Association for Anatomy (AAA), with its expressed and practiced culture of engagement, can serve as a model of best practice for other professional associations working to become more inclusive of individuals from historically underrepresented groups. In this publication, we acknowledge anatomy's exclusionary past, describe the present face of science in academia, and provide recommendations for societies, including the AAA, to accelerate change in academia. We are advocating for scientific societies to investigate inequities and revise practices for inclusivity; develop and empower underrepresented minority leadership; and commit resources in a sustained manner as an investment in underrepresented scientists who bring diverse perspectives and lived experiences to science in academia.
Asunto(s)
Grupos Minoritarios , Sociedades Científicas , Humanos , Liderazgo , Estados UnidosRESUMEN
Heterozygous mutations in SNRPB, an essential core component of the five small ribonucleoprotein particles of the spliceosome, are responsible for cerebrocostomandibular syndrome (CCMS). We show that Snrpb heterozygous mouse embryos arrest shortly after implantation. Additionally, heterozygous deletion of Snrpb in the developing brain and neural crest cells models craniofacial malformations found in CCMS, and results in death shortly after birth. RNAseq analysis of mutant heads prior to morphological defects revealed increased exon skipping and intron retention in association with increased 5' splice site strength. We found increased exon skipping in negative regulators of the P53 pathway, along with increased levels of nuclear P53 and P53 target genes. However, removing Trp53 in Snrpb heterozygous mutant neural crest cells did not completely rescue craniofacial development. We also found a small but significant increase in exon skipping of several transcripts required for head and midface development, including Smad2 and Rere. Furthermore, mutant embryos exhibited ectopic or missing expression of Fgf8 and Shh, which are required to coordinate face and brain development. Thus, we propose that mis-splicing of transcripts that regulate P53 activity and craniofacial-specific genes contributes to craniofacial malformations. This article has an associated First Person interview with the first author of the paper.