The Absence Of MacroH2A Leads To Defects In Brain Development And Autism-like Behaviors In Mice

During the development of the brain,the number of neurons is mainly increased by the symmetrical division of neural precursor cells(NPCs)to generate neurons.In turn,other types of cells such as astrocytes and radial gels are generated through asymmetric development.Plasma cells,etc.,meet the needs of the brain during development.This is a precisely regulated process.Any errors will cause neurodevelopmental abnormalities,which will lead to neurodevelopmental diseases such as autism,two-way mental disorders,etc.In this process,it is regulated by multiple systems and methods,and involves many regulators working together internally and externally.Among many regulation methods,epigenetic regulation plays an important role in the development process.Genomic DNA composed of DNA forms chromatin in the nucleus of eukaryotic cells in a stepwise compression-folding manner.Histone variants are an essential regulatory method in epigenetic regulation,and histone variants play an important role as epigenetic regulatory factors.Among them,other Macron variants of MacroH2A(mH2A)are at the C-terminus.The existence of 25 KD Macro domain has important regulatory functions in life activities due to the specificity of the structure,but its role in brain development is still unknown.This project mainly explores the role of mH2 A in mouse embryonic development through embryo transfer,in vitro immunoblot and small animal behavior analysis.The expression of mH2 A changes with the proliferation and differentiation of neural cells,indicating that mH2 A may be involved The process of neural stem cell proliferation.Decreasing mH2 A expression through embryo electroporation experiments can cause abnormal distribution of GFP-positive cells in the cortex.GFP + is increased in the subventricular zone and the ventricular zone(Ventricular Zone / Subvertricular Zone,VZ / SVZ),and the mitotic markers pH3 and GFP The increase of co-standards of positive cells and PAX positive cells proves that reducing the expression of mH2 A will promote the proliferation of neural stem cells.In addition,we also found that the loss of mH2 A not only led to a reduction in the number of neurons that differentiated,but also that the dendritic development of neurons was abnormal.It is reported in the literature that the gene encoding mH2 A H2Afy is located in the relevant region of the autism risk gene.We have confirmed that mH2A-deficient mice will have social behavior defects,communication difficulties and reduced exploration ability through open field,social,and ultrasound behavioral experiments Autism-like behavior.In order to further explore the mechanism,it was found that the absence of mH2 A caused a decrease in H3K27 acetylation by immunoblotting.It is speculated that mH2 A may be regulated by histone modification.We performed transcriptome gene expression sequencing analysis and found that deletion of mH2 A significantly down-regulated NKX2-2,while overexpression of downstream molecule NKX2-2 could rescue neuron abnormalities caused by deletion of mH2 A.We have demonstrated that mH2 A and NKX2-2 can bind through ChIP experiments.In order to explore how to play a role,we also found that Brd4 is an histidine that can recognize and bind to acetylation,which plays a key role in the transmission of epigenetic memory and transcriptional regulation.effect.Co-IP experiments were used to verify the interaction between mH2 A and Brd4.Co-transfection of lentivirus proved that when mH2 A or Brd4 was down-regulated,the level of H3K27 acetylation decreased.Taken together,these results indicate that mH2 A aggregation Brd4 initiates H3K27 acetylation,which in turn increases downstream NKX2-2 transcriptional expression,which affects cortical development and causes autism-like behavioral defects in mice.