RESUMO
Copy-number changes in 16p11.2 contribute significantly to neuropsychiatric traits. Besides the 600 kb BP4-BP5 CNV found in 0.5%-1% of individuals with autism spectrum disorders and schizophrenia and whose rearrangement causes reciprocal defects in head size and body weight, a second distal 220 kb BP2-BP3 CNV is likewise a potent driver of neuropsychiatric, anatomical, and metabolic pathologies. These two CNVs are engaged in complex reciprocal chromatin looping, intimating a functional relationship between genes in these regions that might be relevant to pathomechanism. We assessed the drivers of the distal 16p11.2 duplication by overexpressing each of the nine encompassed genes in zebrafish. Only overexpression of LAT induced a reduction of brain proliferating cells and concomitant microcephaly. Consistently, suppression of the zebrafish ortholog induced an increase of proliferation and macrocephaly. These phenotypes were not unique to zebrafish; Lat knockout mice show brain volumetric changes. Consistent with the hypothesis that LAT dosage is relevant to the CNV pathology, we observed similar effects upon overexpression of CD247 and ZAP70, encoding members of the LAT signalosome. We also evaluated whether LAT was interacting with KCTD13, MVP, and MAPK3, major driver and modifiers of the proximal 16p11.2 600 kb BP4-BP5 syndromes, respectively. Co-injected embryos exhibited an increased microcephaly, suggesting the presence of genetic interaction. Correspondingly, carriers of 1.7 Mb BP1-BP5 rearrangements that encompass both the BP2-BP3 and BP4-BP5 loci showed more severe phenotypes. Taken together, our results suggest that LAT, besides its well-recognized function in T cell development, is a major contributor of the 16p11.2 220 kb BP2-BP3 CNV-associated neurodevelopmental phenotypes.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/genética , Transtorno Autístico/genética , Encéfalo/patologia , Transtornos Cromossômicos/genética , Cromossomos Humanos Par 16 , Variações do Número de Cópias de DNA , Deficiência Intelectual/genética , Proteínas de Membrana/genética , Microcefalia/genética , Microcefalia/patologia , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/fisiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Transtorno Autístico/imunologia , Transtorno Autístico/patologia , Encéfalo/metabolismo , Criança , Pré-Escolar , Deleção Cromossômica , Transtornos Cromossômicos/imunologia , Transtornos Cromossômicos/patologia , Cromossomos Humanos Par 16/genética , Cromossomos Humanos Par 16/imunologia , Estudos de Coortes , Embrião não Mamífero/metabolismo , Embrião não Mamífero/patologia , Feminino , Regulação da Expressão Gênica no Desenvolvimento , Humanos , Lactente , Deficiência Intelectual/imunologia , Deficiência Intelectual/patologia , Masculino , Proteínas de Membrana/metabolismo , Proteínas de Membrana/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Pessoa de Meia-Idade , Fenótipo , Fosfoproteínas/fisiologia , Transdução de Sinais , Adulto Jovem , Peixe-Zebra/embriologia , Peixe-Zebra/genética , Proteínas de Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismoRESUMO
The 16p11.2 600 kb copy-number variants (CNVs) are associated with mirror phenotypes on BMI, head circumference, and brain volume and represent frequent genetic lesions in autism spectrum disorders (ASDs) and schizophrenia. Here we interrogated the transcriptome of individuals carrying reciprocal 16p11.2 CNVs. Transcript perturbations correlated with clinical endophenotypes and were enriched for genes associated with ASDs, abnormalities of head size, and ciliopathies. Ciliary gene expression was also perturbed in orthologous mouse models, raising the possibility that ciliary dysfunction contributes to 16p11.2 pathologies. In support of this hypothesis, we found structural ciliary defects in the CA1 hippocampal region of 16p11.2 duplication mice. Moreover, by using an established zebrafish model, we show genetic interaction between KCTD13, a key driver of the mirrored neuroanatomical phenotypes of the 16p11.2 CNV, and ciliopathy-associated genes. Overexpression of BBS7 rescues head size and neuroanatomical defects of kctd13 morphants, whereas suppression or overexpression of CEP290 rescues phenotypes induced by KCTD13 under- or overexpression, respectively. Our data suggest that dysregulation of ciliopathy genes contributes to the clinical phenotypes of these CNVs.
Assuntos
Transtornos Globais do Desenvolvimento Infantil/genética , Cromossomos Humanos Par 16/genética , Variações do Número de Cópias de DNA/genética , Esquizofrenia/genética , Animais , Encéfalo , Criança , Transtornos Globais do Desenvolvimento Infantil/patologia , Deleção Cromossômica , Corpo Ciliar/metabolismo , Corpo Ciliar/patologia , Regulação da Expressão Gênica , Humanos , Camundongos , Canais de Potássio de Abertura Dependente da Tensão da Membrana/genética , Esquizofrenia/patologia , Transcriptoma , Peixe-Zebra , Proteínas de Peixe-Zebra/genéticaRESUMO
BACKGROUND: Smith-Magenis syndrome (SMS) is a developmental disability/multiple congenital anomaly disorder resulting from haploinsufficiency of RAI1. It is characterized by distinctive facial features, brachydactyly, sleep disturbances, and stereotypic behaviors. METHODS: We investigated a cohort of 15 individuals with a clinical suspicion of SMS who showed neither deletion in the SMS critical region nor damaging variants in RAI1 using whole exome sequencing. A combination of network analysis (co-expression and biomedical text mining), transcriptomics, and circularized chromatin conformation capture (4C-seq) was applied to verify whether modified genes are part of the same disease network as known SMS-causing genes. RESULTS: Potentially deleterious variants were identified in nine of these individuals using whole-exome sequencing. Eight of these changes affect KMT2D, ZEB2, MAP2K2, GLDC, CASK, MECP2, KDM5C, and POGZ, known to be associated with Kabuki syndrome 1, Mowat-Wilson syndrome, cardiofaciocutaneous syndrome, glycine encephalopathy, mental retardation and microcephaly with pontine and cerebellar hypoplasia, X-linked mental retardation 13, X-linked mental retardation Claes-Jensen type, and White-Sutton syndrome, respectively. The ninth individual carries a de novo variant in JAKMIP1, a regulator of neuronal translation that was recently found deleted in a patient with autism spectrum disorder. Analyses of co-expression and biomedical text mining suggest that these pathologies and SMS are part of the same disease network. Further support for this hypothesis was obtained from transcriptome profiling that showed that the expression levels of both Zeb2 and Map2k2 are perturbed in Rai1 -/- mice. As an orthogonal approach to potentially contributory disease gene variants, we used chromatin conformation capture to reveal chromatin contacts between RAI1 and the loci flanking ZEB2 and GLDC, as well as between RAI1 and human orthologs of the genes that show perturbed expression in our Rai1 -/- mouse model. CONCLUSIONS: These holistic studies of RAI1 and its interactions allow insights into SMS and other disorders associated with intellectual disability and behavioral abnormalities. Our findings support a pan-genomic approach to the molecular diagnosis of a distinctive disorder.
Assuntos
Exoma/genética , Redes Reguladoras de Genes , Genômica/métodos , Mutação/genética , Síndrome de Smith-Magenis/genética , Fatores de Transcrição/fisiologia , Transcriptoma , Animais , Embrião de Mamíferos/citologia , Embrião de Mamíferos/metabolismo , Feminino , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fenótipo , RNA Mensageiro/genética , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , TransativadoresRESUMO
Supravalvular aortic stenosis is a systemic elastin (ELN) arteriopathy that disproportionately affects the supravalvular aorta. ELN arteriopathy may be present in a nonsyndromic condition or in syndromic conditions such as Williams-Beuren syndrome. The anatomic findings include congenital narrowing of the lumen of the aorta and other arteries, such as branches of pulmonary or coronary arteries. Given the systemic nature of the disease, accurate evaluation is recommended to establish the degree and extent of vascular involvement and to plan appropriate interventions, which are indicated whenever hemodynamically significant stenoses occur. ELN arteriopathy is genetically heterogeneous and occurs as a consequence of haploinsufficiency of the ELN gene on chromosome 7q11.23, owing to either microdeletion of the entire chromosomal region or ELN point mutations. Interestingly, there is a prevalence of premature termination mutations resulting in null alleles among ELN point mutations. The identification of the genetic defect in patients with supravalvular aortic stenosis is essential for a definitive diagnosis, prognosis, and genetic counseling.
Assuntos
Aorta/patologia , Estenose Aórtica Supravalvular/patologia , Elastina/metabolismo , Aorta/diagnóstico por imagem , Estenose Aórtica Supravalvular/diagnóstico , Estenose Aórtica Supravalvular/diagnóstico por imagem , Estenose Aórtica Supravalvular/etiologia , Diagnóstico Diferencial , Elastina/genética , Humanos , Síndrome , UltrassonografiaRESUMO
Transposable elements, as major components of most eukaryotic organisms' genomes, define their structural organization and plasticity. They supply host genomes with functional elements, for example, binding sites of the pleiotropic master transcription factor p53 were identified in LINE1, Alu and LTR repeats in the human genome. Similarly, in this report we reveal the role of zebrafish (Danio rerio) EnSpmN6_DR non-autonomous DNA transposon in shaping the repertoire of the p53 target genes. The multiple copies of EnSpmN6_DR and their embedded p53 responsive elements drive in several instances p53-dependent transcriptional modulation of the adjacent gene, whose human orthologs were frequently previously annotated as p53 targets. These transposons define predominantly a set of target genes whose human orthologs contribute to neuronal morphogenesis, axonogenesis, synaptic transmission and the regulation of programmed cell death. Consistent with these biological functions the orthologs of the EnSpmN6_DR-colonized loci are enriched for genes expressed in the amygdala, the hippocampus and the brain cortex. Our data pinpoint a remarkable example of convergent evolution: the exaptation of lineage-specific transposons to shape p53-regulated neuronal morphogenesis-related pathways in both a hominid and a teleost fish.