In the head,
elt-3 GFP expression decreases with age in the hypodermal cells and the pharyngeal-intestinal valve cells, eventually showing little or no expression in old worms. In the trunk,
elt-3 expression is mostly derived from the hypodermal cells and the intestinal cells, and expression in this region decreases quickly between day 3 and day 5 of adulthood. The
elt-3 GFP reporter did not change expression in the intestinal-rectal valve cells located in the tail of the worm. In summary, these results show that age-related changes in
elt-3 expression are complex, as different tissues show different kinetics of age regulation and some tissues show no age regulation at all.