Transgenic animals containing the
fos-1a::YFP-TX and -TL reporters showed the same expression pattern at all times examined, and
fos-1a::YFP-TL protein localized to the nucleus.
fos-1a::YFP-TL also rescued the AC-invasion defect when expressed in
fos-1(
ar105) mutants.
fos-1a was expressed at the highest level in the AC and at lower levels in neighboring somatic gonad cells during AC invasion. No expression of
fos-1a was detected in vulval cells. In contrast, both the
fos-1b::CFP-TX and -TL reporters directed expression in vulval cells and the AC.
fos-1b::CFP-TL also drove expression in neighboring uterine cells, whereas
fos-1b::CFP-TX did not, suggesting the presence of a downstream uterine enhancer element in
fos-1b::CFP-TL. Unlike
fos-1a expression, levels of
fos-1b::CFP-TL protein were not greater in the AC compared to neighboring cells. Moreover, whereas the
fos-1a reporters drove expression almost exclusively in the somatic gonad cells, the
fos-1b reporters directed expression in nearly all cells at the L3 stage.