RESUMEN
The cytoplasm in mammalian cells is considered homogeneous. In this study, we report that the cytoplasmic fluidity is regulated in the blebbing cells; the cytoplasm of rapidly expanding membrane blebs is more disordered than the cytoplasm of retracting blebs. The increase of cytoplasmic fluidity in the expanding bleb is caused by a sharp rise in the calcium concentration. The STIM-Orai1 pathway regulates this rapid and restricted increase of calcium in the expanding blebs. Conversely, activated ERM protein binds to Orai1 to inhibit the store-operated calcium entry in retracting blebs, which results in decreased in cytoplasmic calcium, rapid reassembly of the actin cortex.
Asunto(s)
Calcio/metabolismo , Membrana Celular/metabolismo , Citoplasma/metabolismo , Proteína ORAI1/metabolismo , Molécula de Interacción Estromal 1/metabolismo , Citoesqueleto de Actina , Actinas/metabolismo , Animales , Señalización del Calcio/fisiología , Línea Celular , Línea Celular Tumoral , Proteínas del Citoesqueleto/antagonistas & inhibidores , Células HEK293 , Humanos , Proteínas de la Membrana/fisiologíaRESUMEN
SETD1A encodes a histone methyltransferase whose de novo mutations are identified in schizophrenia (SCZ) patients and confer a large increase in disease risk. Here, we generate Setd1a mutant mice carrying the frameshift mutation that closely mimics a loss-of-function variant of SCZ. Our Setd1a (+/-) mice display various behavioral abnormalities relevant to features of SCZ, impaired excitatory synaptic transmission in layer 2/3 (L2/3) pyramidal neurons of the medial prefrontal cortex (mPFC), and altered expression of diverse genes related to neurodevelopmental disorders and synaptic functions in the mPFC. RNAi-mediated Setd1a knockdown (KD) specifically in L2/3 pyramidal neurons of the mPFC only recapitulates impaired sociality among multiple behavioral abnormalities of Setd1a (+/-) mice. Optogenetics-assisted selective stimulation of presynaptic neurons combined with Setd1a KD reveals that Setd1a at postsynaptic site is essential for excitatory synaptic transmission. Our findings suggest that reduced SETD1A may attenuate excitatory synaptic function and contribute to the pathophysiology of SCZ.
Asunto(s)
Conducta Animal , N-Metiltransferasa de Histona-Lisina/deficiencia , Esquizofrenia/fisiopatología , Sinapsis/fisiología , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Sistemas CRISPR-Cas/genética , Potenciales Postsinápticos Excitadores/fisiología , Femenino , Eliminación de Gen , Regulación de la Expresión Génica , Ácido Glutámico/metabolismo , N-Metiltransferasa de Histona-Lisina/química , N-Metiltransferasa de Histona-Lisina/genética , N-Metiltransferasa de Histona-Lisina/metabolismo , Humanos , Masculino , Ratones Endogámicos ICR , Mutación/genética , Trastornos del Neurodesarrollo/genética , Corteza Prefrontal/metabolismo , Terminales Presinápticos/fisiología , Células Piramidales/metabolismo , Esquizofrenia/genética , Conducta SocialRESUMEN
Neural progenitor cells (NPCs, also known as radial glial progenitors) produce neurons and then glial cells such as astrocytes during development of the mouse neocortex. Given that this sequential generation of neural cells is critical for proper brain formation, the neurogenic potential of NPCs must be precisely controlled. Here, we show that the transcription factor Plag1 plays an important role in the regulation of neurogenic potential in mouse neocortical NPCs. We found that Hmga2, a key neurogenic factor in neocortical NPCs, induces expression of the Plag1 gene. Analysis of the effects of over-expression or knockdown of Plag1 indicated that Plag1 promotes the production of neurons at the expense of astrocyte production in embryonic neocortical cultures. Furthermore, over-expression of Plag1 promoted and knockdown of Plag1 suppressed neuronal differentiation of neocortical NPCs in vivo. Transcriptomic analysis showed that Plag1 increases the expression of a set of neuronal genes in NPCs. Our results thus identify Plag1 as a regulator of neuronal gene expression and neuronal differentiation in NPCs of the developing mouse neocortex.
