The reporter transgenes express ubiquitously in the early embryo starting at about the 100 cell stage during gastrulation. In late embryogenesis and posthatching, expression is more limited. Strongest expression is observed in migrating cells and growing neurons as these cells undergo movements on the epidermis. At hatching, the reporters express in many neurons throughout the animal, in several cells of the pharynx including some pharyngeal neurons, in the elongated processes of the excretory cells, in the amphid and phasmid sheath and socket cells, in the tail hypodermis, and at later stages in intestine, muscles, vulva, and somatic gonad including the gonad sheath and hermaphrodite distal tip cells. The neurons expressing
unc-73 include the PLM, ALM, PDE, HSN, CAN, PHC, and PVN neurons and the ventral cord motorneurons. Expression in the HSNs is absent in early larval stages, but begins late in the second larval stage (L2), precisely when axon outgrowth is initiated from the HSN cell bodies. The Q neuroblasts, Pn neuroectoblasts, sex myoblasts (SMs), and canal associated neurons (CANs) express
unc-73 reporters. The left and right Q cells begin to express the GFP reporter as they initiate their migrations along the longitudinal axis of the epidermis during the early first larval (L1) stage, and expression in these cells continues beyond the completion of their first division. The
unc-73 reporters express in the Pn cells just before this second phase of movemen. The distal tip cells also express the
unc-73/reporters during their migration.