Fig. 1. Ectopic HLH-1 activity converts most somatic blastomeres to a body wall muscle-like fate. (Left) Diagrams of wild-type embryos at the comma stage of development [adapted from Sulston et al. (Sulston et al., 1983)] with four different cell type patterns highlighted by nuclei or tissue area shading; body wall muscle (BWM), intestine (Int); hypodermis (Hyp) and pharynx (Phar). Adjacent to each diagram is a wild-type embryo stained with an antibody recognizing the corresponding tissue and imaged in a single focal plane. The far right column shows terminally arrested embryos in which HLH-1 activity was induced in early development by heat shock treatment. All embryos showed widespread myogenesis as indicated by MHC A staining in a representative focal plane from throughout the embryo (top) and a complete lack of staining for markers of the intestine, hypodermis and pharynx (below). All images in this and subsequent figures are a single focal plane deconvoluted using Hyguens software.