This is the first report of proteomic alterations following embryonic exposure to atrazine, an environmentally persistent pesticide and common water contaminant. Although the transcriptomic alterations in larval zebrafish with embryonic atrazine exposure have been reported, neither the time at which gene expression changes occur nor the resulting proteomic changes have been investigated. This study seeks to address these knowledge gaps by evaluating atrazine's effect on gene expression through multiple time points during embryogenesis, and correlating changes in gene expression to pathological alterations in brain length and functional changes in behavior. Finally, pathway analysis of the proteomic alterations identifies connections between the molecular changes and functional outcomes associated with embryonic atrazine exposure.

Atrazine is an herbicide commonly applied to crops in the Midwest part of the United States. The chemical moves into drinking water sources after rainfall events, which increases the risk of human exposure. The United States Environmental Protection Agency set the maximum contaminant level at 3 parts per billion (ppb) in drinking water, but even these levels are suspected to cause adverse health eff ects. Developmental exposure to atrazine is reported to increase birth defects and result in endocrine disruption.