hlh-2,
hlh-3, and
hlh-4 are all expressed in ADL neurons but in a temporal specific manner. While
hlh-2 is expressed in ADL throughout development from the embryo to the adult consistent with previous reports, we find that both
hlh-3 and
hlh-4 are transiently expressed in ADL. Expression of
hlh-3 in ADL is observed in the late embryo before hatching, but not in L2 larvae or in adults. However, it remains possible that
hlh-3 is very lowly expressed in ADL. In contrast, we observed that
hlh-4 is expressed in ADL neurons in L1 larvae and in adults, but we did not observe
hlh-4 expression in ADL in late-staged embryos before hatching. We observed that similar to
hlh-4,
hlh-10 is expressed in ADL neurons in larvae and adults, again opposite to the expression of
hlh-3 observed in ADL. Thus, while
hlh-2 is expressed in ADL throughout development,
hlh-3 and
hlh-4 may be transiently expressed in ADL.