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Bieler, R. A.

Publications and source records attributed to Bieler, R. A..

2 recordsLinked to original sources

Multi-omic analyses identify molecular targets of Chd7 that mediate CHARGE syndrome model phenotypes

CHARGE syndrome is a developmental disorder that affects 1 in 10,000 births, and patients exhibit both physical and behavioral characteristics. De novo mutations in CHD7 (chromodomain helicase DNA binding protein 7) cause 67% of CHARGE syndrome cases. CHD7 is a DNA-binding chromatin remodeler with thousands of predicted binding sites in the genome, making it challenging to define molecular pathways linking loss of CHD7 to CHARGE phenotypes. To address this problem, here we used a previously characterized zebrafish CHARGE model to generate transcriptomic and proteomic datasets from larval zebrafish head tissue at two developmental time points. By integrating these datasets with differential expression, pathway, and upstream regulator analyses, we identified multiple consistently dysregulated pathways and defined a set of candidate genes that link loss of chd7 with disease-related phenotypes. Finally, to functionally validate the roles of these genes, CRISPR/Cas9-mediated knockdown of capgb, nefla, or rdh5 phenocopies behavioral defects seen in chd7 mutants. Our data provide a resource for further investigation of molecular mediators of CHD7 and a template to reveal functionally relevant therapeutic targets to alleviate specific aspects of CHARGE syndrome. Summary StatementWe have identified Chd7 target genes capgb, nefla, and rdh5 that mediate CHARGE model phenotypes from transcriptomic and proteomic analysis of chd7 wild type, heterozygous, and homozygous mutant zebrafish brain tissue at two developmental time points.

neuroscience↗

Effects of 4 testing arena sizes and 11 types of embryo media on sensorimotor behaviors in wild-type and chd7 mutant zebrafish larvae

The larval zebrafish is a highly versatile model across research disciplines, and the expanding use of behavioral analysis has contributed to many advances in neuro-psychiatric, developmental, and toxicological studies, often through large-scale chemical and genetic screens. In the absence of standardized approaches to larval zebrafish behavior analysis, however, it is critical to understand the impact on behavior of experimental variables such as the size of testing arenas and the choice of embryo medium. Using a custom-built, modular high-throughput testing system, we examined the effects of 4 testing arena sizes and 11 types of embryo media on conserved sensorimotor behaviors in zebrafish larvae. Our data show that testing arena size impacts acoustic startle sensitivity and kinematics as well as spontaneous locomotion and thigmotaxis, with fish tested in larger arenas displaying reduced startle sensitivity and increased locomotion. We also find that embryo media can dramatically affect startle sensitivity, kinematics, habituation, and pre-pulse inhibition, as well as spontaneous swimming, turning, and overall activity. Common media components such as methylene blue and high calcium concentration consistently reduced startle sensitivity and locomotion. To further address how the choice of embryo medium can impact phenotype expression in zebrafish models of disease, we reared chd7 mutant larvae, a model of CHARGE syndrome with previously characterized morphological and behavioral phenotypes, in 5 different types of media and observed impacts on all phenotypes. By defining the effects of these key extrinsic factors on larval zebrafish behavior, these data can help researchers select the most appropriate conditions for their specific research questions, particularly for genetic and chemical screens.

neuroscience↗