Identification of a molecular network regulated by multiple ASD high risk genes.

Genetic sequencing has identified high-confidence ASD risk genes with loss-of-function mutations. How the haploinsufficiency of distinct ASD risk genes causes ASD remains to be elucidated. In this study, we examined the role of four top-ranking ASD risk genes, ADNP, KDM6B, CHD2, and MED13, in gene expression regulation. ChIP-seq analysis reveals that gene targets with the binding of these ASD risk genes at promoters are enriched in RNA processing and DNA repair. Many of these targets are found in ASD gene database (SFARI), and are involved in transcription regulation and chromatin remodeling. Common gene targets of these ASD risk genes include a network of high confidence ASD genes associated with gene expression regulation, such as CTNNB1 and SMARCA4. We further directly examined the transcriptional impact of the deficiency of these ASD risk genes. Our mRNA profiling with qPCR assays in cells with the knockdown of Adnp, Kdm6b, Chd2 or Med13 has revealed an intricate pattern of their cross-regulation, as well as their influence on the expression of other ASD genes. In addition, some synaptic genes, such as Snap25 and Nrxn1, are strongly regulated by deficiency of the four ASD risk genes, which could be through the direct binding at promoters or indirectly through the targets like Ctnnb1 or Smarca4. The identification of convergent and divergent gene targets that are regulated by multiple ASD risk genes will help to understand the molecular mechanisms underlying common and unique phenotypes associated with haploinsufficiency of ASD-associated genes.