Morphogenesis is also dependent on muscle which is structurally connected to the hypodermis.
Mosaic analysis demonstrates that mup-4 is not essential in embryonic muscle since it is required in the AB lineage which gives rise primarily to hypodermal and neuronal cells. Consistent with a proposed function in the hypodermis, hypodermal cells are twisted around the embryo and hypodermal seam cells appear not to connect to the proper neighbor. Furthermore, at the bean stage, mup-4 mutants have abnormal hypodermal cell shapes. We currently favor the latter hypothesis based on aspects of the mup-4 phenotype. Molecular analysis of mup-4 provides the opportunity to investigate embryonic cell interactions that are essential for morphogenesis.