is an orthologue of the vertebrate Lim3 homeobox genes. From the lacZ and GFP transgenic lines we observe the following expression patterns: Expression in blast cells in the anterior and posterior during embryogenesis. The expression in the anterior, i.e., the head, disappears or is strongly reduced in larval stages. Additional neurons, which are generated during postembryonic cell divisions are expressing ceh-14
in the tail. The following neurons in the body and tail were identified: BDUL/R, PVT, DVC, PHAL/R, PHBL/R, PHCL/R, PVNL/R, and tentatively PVWL/R, PVR. Apart from the neuronal expression, nuclear staining is seen in the spermatheca and in the central hypodermis of young hermaphrodites. The hypodermal expression has the appearance of a gradient, being stronger in the center and getting weaker towards the anterior and posterior. To test this hypothesis, we examined the expression in male animals. Indeed, the hypodermal gradient was now localized in the male tail, rather than in the central body, suggesting that signaling systems responsible for the sexual dimorphism also control the expression of ceh-14
. We tested whether the mutations of known signaling systems would change the pattern of ceh-14
expression. However, expression in the background of a lin-3
mutation did not show any difference. Neither did we observe any differences in a lin-12
mutation. Experiments using laser ablation of the gonad precursor cells are currently underway in collaboration with Ralf Sommer. We isolated cDNAs for ceh-14
, which confirmed the predicted gene structure of our genomic sequence. ceh-7
is a tiny orphan homeobox gene. A GFP construct shows specific restricted expression in only a few male tail cells, probably B decendents. This is the first case of a sex-specific homeobox gene.