Identification of neuron‐specific promoters in Ciona intestinalis

Abstract

We isolated 5′ flanking regions of four genes, Ci-Gαi1, Ci-arr, Ci-vAChTP,, and Ci-vGAT, each of which is expressed in distinct sets of neurons in the central nervous system of the ascidian Ciona intestinalis, and we examined their function by introducing green fluorescent protein (GFP)-fusion constructs into Ciona embryos. The reporter gene driven by the 5′ flanking region of Ci-Gαi1, Ci-arr, and Ci-vAChTP recapitulated the endogenous gene expression patterns, while that of Ci-vGAT can drive GFP expression in particular subsets of neurons expressing the endogenous gene. Deletion analysis revealed that the Ci-Gαi1 promoter consists of multiple regulatory modules controlling the expression in different types of cells. The GFP fluorescence enabled visualization of cell bodies and axons of different sets of neurons in ascidian larvae. These promoters can be a powerful tool for studying molecular mechanisms of neuronal development as well as neuron networks and functions in ascidians. genesis 39:130–140, 2004.