Neuronal Histone Methyltransferase EZH2 Regulates Neuronal Morphogenesis, Synaptic Plasticity, and Cognitive Behavior in Mice / 神经科学通报·英文版

The histone methyltransferase enhancer of zeste 2 polycomb repressive complex 2 subunit (EZH2)-mediated trimethylation of histone H3 lysine 27 (H3K27me3) regulates neural stem cell proliferation and fate specificity through silencing different gene sets in the central nervous system. Here, we explored the function of EZH2 in early post-mitotic neurons by generating a neuron-specific Ezh2 conditional knockout mouse line. The results showed that a lack of neuronal EZH2 led to delayed neuronal migration, more complex dendritic arborization, and increased dendritic spine density. Transcriptome analysis revealed that neuronal EZH2-regulated genes are related to neuronal morphogenesis. In particular, the gene encoding p21-activated kinase 3 (Pak3) was identified as a target gene suppressed by EZH2 and H3K27me3, and expression of the dominant negative Pak3 reversed Ezh2 knockout-induced higher dendritic spine density. Finally, the lack of neuronal EZH2 resulted in impaired memory behaviors in adult mice. Our results demonstrated that neuronal EZH2 acts to control multiple steps of neuronal morphogenesis during development, and has long-lasting effects on cognitive function in adult mice.

Síndrome de Sotos diagnosticado por hibridación genómica comparativa / Sotos syndrome diagnosed by comparative genomic hybridisation

El síndrome de Sotos (SS) es una enfermedad genética con un patrón de herencia autosómico dominante, causado por haploinsuficiencia del gen NSD1 secundaria a mutaciones puntuales o microdeleciones del locus 5q35 en el que está ubicado el gen. Es un síndrome poco frecuente, presentándose en 7 de cada 100.000 nacimientos. El objetivo de este reporte es presentar el caso de una paciente de 4 años con retardo global del desarrollo, y hallazgos físicos especiales que sugerían un sindrome genético. Caso clínico: Paciente de 4 años, género femenino, cabello ralo, fascie triangular, fisura palpebral alargada, papadar ojival, mandíbula prominente, escápula alada y clinodactilia del quinto dedo de ambas manos. La prueba molecular de hibridación genómica comparativa por microarreglos, mostró microdeleción de la región 5q35.2 q35.3 de 2.082 MB, que incluye el gen NSD1. Conclusión: Proponemos realizar la prueba de hibridación genómica comparativa en pacientes con retraso global del desarrollo y hallazgos fenotípicos menores.

Sotos Syndrome (SS) is a genetic disease with an autosomal dominant pattern caused by haplo-insufficiency of NSD1 gene secondary to point mutations or microdeletion of the 5q35 locus where the gene is located. It is a rare syndrome, occurring in 7 out of every 100,000 births. The objective of this report is to present the case of a 4 year-old patient with a global developmental delay, as well as specific physical findings suggesting a syndrome of genetic origin. Clinical case: Female patient, 4 years of age, thinning hair, triangular facie, long palpebral fissure, arched palate, prominent jaw, winged scapula and clinodactilia of the fifth finger both hands. The molecular test comparative genomic hybridisation test by microarray was subsequently performed, with the result showing 5q35.2 q35.3 region microdeletion of 2,082 MB, including the NSD1 gene. Conclusion: Finally, this article also proposes the performing of comparative genomic hybridisation as the first diagnostic option in cases where clinical findings are suggestive of SS.