glp-1 is likely expressed in neurons. A GFP reporter was constructed containing 2.5 kb of putative regulatory sequence upstream and downstream of the
glp-1 translation start site (
glp-1p::gfp; see Supplemental methods for details). GFP expression was observed near the excretory pore, anus, in vulval precursor cells, intestinal cells, and in a few head neurons that could not be identified due to low expression levels. Previous studies indicated that
glp-1 activation increases
glp-1 transcription [11,12,13,14]. As the
glp-1 reporter construct described above contains numerous binding sites for LAG-1, a C. elegans homolog of the CSL/Su(H) transcription factor homolog that is critical for Notch transcriptional activation of target genes, we reasoned that over-expressing
osm-11 might lead to increased
glp-1p::gfp expression. Within hours heat shock induction of OSM-11 expression, GFP expression was clearly observed in many neurons of hsp::
osm-11;
glp-1p::gfp transgenic animals. These neurons included ASG, ASH, ASI, ADL, ASJ, ADF, and ASE sensory neurons, but not the RIG interneurons that express
lin-12. The ASH, ADL, and AWB sensory neurons detect octanol semi-redundantly [4,15] suggesting that
glp-1 might act to modulate octanol response in these sensory neurons. Shown here is
glp-1p::gfp expression in head neurons (arrow indicates ASHR ). Scale bar represents 10 m.