sem-2 expression was identified in several early blastomeres and in some neuronal and non-neuronal progenitors. Its expression colocalized with that of
sox-2 in a few progenitors. As in vertebrates,
sem-2 expression was observed in postmitotic neurons, but in contrast to the broad expression of SoxC genes in vertebrate postmitotic neurons, only a single class of postembryonic neurons expresses
sem-2, the RMH class.
sem-2 expression in these neurons is observed throughout larval and adult stages. We did not detect any
sem-2 expression in the RME neurons themselves, but
sem-2 is instead expressed in the progenitor of RMEL/R.