In C. elegans embryos, H1.X::GFP expression starts with the 30-cell stage. The most prominent structures labeled with both antibodies as well as with H1.X::GFP in transgenic animals are the marginal cells and the tonofilaments therein. The signal appears in all larval stages and in adult C. elegans. No further nuclear or cytoplasmic signal appears besides the labeling of all nuclear lamina caused by the anti-lamin crossreactivity of H1.X-11. This result is confirmed by independent antibody labeling with H1.X-101. In these preparations no nuclear signal appeared in the nuclei of the marginal cells, although the cytoplasm of some head neurons was stained.
The C+C enhancer (pOK17.21) activates frequent expression in all pharyngeal muscles. the C+C enhancer also activates expression in non-muscle cells in the pharynx. Expression induced by the C+C enhancer was observed in all pharyngeal cell types including gland cells, neurons and marginal cells as well as muscles. These results define C as an organ-specific subelement.