T4. USING DROSOPHILA TO STUDY THE FUNCTIONALITY OF A CHROMATIN REGULATORY GENE INVOLVED IN ASD

Background Autism spectrum disorder (ASD) is a heterogeneous genetic syndrome characterized by social deficits, language impairments and repetitive behaviors. We now know that autism could be triggered by different types of genetic variations in different types of genes. Chromatin regulator genes found to be one of the most enriched group of genes disrupted in ASD. We suggest using Drosophila models for studying the chromatin related genes that are disrupted in ASD. Recently, several papers studied and found individuals with POGZ de novo disruptive mutations and defined shared phenotypes including developmental delay, vision problems, microcephaly, hyperactivity and tendency to obesity. All this information lead POGZ gene to consider as a high risk ASD and ID gene. POGZ involved in chromatin regulation, binds different isotypes of the human heterochromatin protein 1 (HP1α, HP1β and HP1γ) To identify orthologs of POGZ in Drosophila we used both a reverse Blast method and treefam database. We identified the gene ROW as the Drosophila ortholog of POGZ. Similar to POGZ, ROW was identified as a binding partner of heterochromatin protein 1, HP1c and HP1B. Methods We used flies with knockdown of ROW and cloned the gene into the UAS/GAL4 system in order to establish flies with its overexpression. We examine the behavior of the affected flies and currently the effects of ROW knockdown on transcription and on chromatin state by RNA-seq, MNase-seq and Chip seq in the context of the nervous system. We also aim to perform Co-IP experiment in order to find ROWu0027s binding partner in the nervous system. Results We show that once the efficiency of the knockdown in the protein level is highly significant, those flies show partial lethality, shorter life span, fertility and sleeping problems. Moreover, Ubiquitous overexpression of ROW lead to complete lethality of the flies, therefore we used conditional system expressed only in neurons. By analysis of Chip-seq data we show ROW overlaps with histone modifications and proteins associate with transcriptional activation. Therefore, currently we work on examining its effects on transcription and on chromatin state. Discussion Here we show our attempts towards establishing a Drosophila model for the POGZ ortholog, ROW. We expect the model to help us characterize the role of ROW in the Drosophila nervous system and understand the functional relevance of POGZ to ASD.