RESUMEN
Microcephaly is a neurodevelopmental disorder causing significantly reduced cerebral cortex size. Many known microcephaly gene products localize to centrosomes, regulating cell fate and proliferation. Here, we identify and characterize a nuclear zinc finger protein, ZNF335/NIF-1, as a causative gene for severe microcephaly, small somatic size, and neonatal death. Znf335 null mice are embryonically lethal, and conditional knockout leads to severely reduced cortical size. RNA-interference and postmortem human studies show that ZNF335 is essential for neural progenitor self-renewal, neurogenesis, and neuronal differentiation. ZNF335 is a component of a vertebrate-specific, trithorax H3K4-methylation complex, directly regulating REST/NRSF, a master regulator of neural gene expression and cell fate, as well as other essential neural-specific genes. Our results reveal ZNF335 as an essential link between H3K4 complexes and REST/NRSF and provide the first direct genetic evidence that this pathway regulates human neurogenesis and neuronal differentiation.
Asunto(s)
Proteínas Portadoras/metabolismo , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Células-Madre Neurales/metabolismo , Neurogénesis , Proteínas Nucleares/metabolismo , Animales , Diferenciación Celular , Proliferación Celular , Proteínas de Unión al ADN , Femenino , Técnicas de Silenciamiento del Gen , Genes Letales , N-Metiltransferasa de Histona-Lisina , Humanos , Masculino , Ratones , Ratones Noqueados , Microcefalia/metabolismo , Complejos Multiproteicos/metabolismo , Proteína de la Leucemia Mieloide-Linfoide/metabolismo , Proteínas Represoras/metabolismo , Factores de TranscripciónRESUMEN
Nucleotide excision repair (NER) defects are associated with cancer, developmental disorders and neurodegeneration. However, with the exception of cancer, the links between defects in NER and developmental abnormalities are not well understood. Here, we show that the ERCC1-XPF NER endonuclease assembles on active promoters in vivo and facilitates chromatin modifications for transcription during mammalian development. We find that Ercc1(-/-) mice demonstrate striking physiological, metabolic and gene expression parallels with Taf10(-/-) animals carrying a liver-specific transcription factor II D (TFIID) defect in transcription initiation. Promoter occupancy studies combined with expression profiling in the liver and in vitro differentiation cell assays reveal that ERCC1-XPF interacts with TFIID and assembles with POL II and the basal transcription machinery on promoters in vivo. Whereas ERCC1-XPF is required for the initial activation of genes associated with growth, it is dispensable for ongoing transcription. Recruitment of ERCC1-XPF on promoters is accompanied by promoter-proximal DNA demethylation and histone marks associated with active hepatic transcription. Collectively, the data unveil a role of ERCC1/XPF endonuclease in transcription initiation establishing its causal contribution to NER developmental disorders.