Figure 1 Identification of the minimal
trx-1 promoter region necessary for gene expression in ASJ neurons. (A) Bright-field (BF, top) and fluorescence (bottom) images of Ptrx-1(1kb)::gfp transgenic animals. ASJR (ASJ right) and ASJL (ASJ left) neurons are indicated. When expressed from the
trx-1 promoter, GFP is found in the entire cell: in cilia, dendrites, cell bodies, and axons. Bar, 20 um. (B) Identification of the minimal
trx-1 promoter region that drives gene expression in ASJ neurons. Decreasing length fragments of the
trx-1 promoter fused to the GFP-coding sequence have identified an ASJ minimal promoter (dotted blue line) located at position 2200 to 284 upstream of the
trx-1a ATG codon. (C) Serial deletions within the
trx-1 minimal promoter region previously identified reveal the sequence 2200 to 2173 (dotted blue line) upstream of the
trx-1a ATG codon as necessary for gene expression in ASJ neurons. For quantification, at least 50 animals per line were analyzed. (D) Transgenic animals expressing a 33 tandem construct of the sequence 2200 to 2173 (necessary for gene expression in ASJ) fused to GFP show fluorescence in head neurons with morphology and position consistent with being ASJ. The asterisk indicates the ASJ cell body, and the arrowhead points to the ASJ dendrite. Bar, 5 um.