Abstract
The generation of cellular diversity is dependent on the precise spatiotemporal regulation of gene expression by both cis- and trans-acting mechanisms. The developmental principles regulating expression of specific gene subsets in individual cell types are not fully understood. Here we define the cis-regulatory mechanisms driving expression of cell-selective and broadly expressed genes in vivo in the AWB olfactory neuron subtype in C. elegans. We identify an element that is necessary to drive expression of neuron-selective chemoreceptor genes in the AWB neurons, and show that this element functions in a context-dependent manner. We find that the expression of broadly expressed sensory neuronal genes in the AWB neurons is regulated by diverse cis- and trans-regulatory mechanisms that act partly in parallel to the pathways governing expression of AWB-selective genes. We further demonstrate that cis-acting mechanisms driving gene expression in the AWB neurons appear to have diverged in related nematode species. Our results provide insights into the cis-regulatory logic driving cell-specific gene expression, and suggest that variations in this logic contribute to the generation of functional diversity.