3D Structure of the Tyrosine Hydroxylase Locus in Undifferentiated and Differentiated SH-SY5Y cells

Indianapolis, IN

Correct regulation of gene expression is crucial for proper cellular function, including during differentiation from one cell type to another. The tyrosine hydroxylase gene (TH) has been implicated in dopaminergic neuron differentiation – the gene is not expressed in undifferentiated dopaminergic neurons, but is highly expressed in differentiated dopaminergic neurons. It has been well established that changes in three-dimensional (3D) chromosome conformation accompany changes in gene expression. These changes in chromosome structure involve crucial regulatory elements, such as enhancers, creating a 3D contact with a target gene promoter. The changes in 3D structure at the TH locus during cellular differentiation have yet to be determined. We studied the 3D structure of the TH locus in two different cell types: undifferentiated human neuron-like SH-SY5Y cells where TH expression is low or absent, and differentiated SH-SY5Y cells where TH is highly expressed. We performed a bioinformatics analysis to identify potential enhancer sites at the TH locus. Next, we performed chromosome conformation capture (3C) experiments on both cell types to determine their 3D structure. We present our current progress on this project. Understanding the regulatory landscape of TH and its neighbors will inform not only our basic understanding of gene regulatory mechanisms, but will additionally provide insight into potential locations of extragenic mutations that could contribute to diseases of dopaminergic dysfunction such as Parkinson’s disease, mood disorders, autism, schizophrenia, and ADHD.