Fig. 1. The Spatial Control Region of the glp-1 3' UTR is sufficient for translational control in the embryo. (A) A diagram of a single hermaphrodite gonad arm. Mitotic germ cells proliferate near the distal end, and as they move from this region they enter meiosis, differentiate into oocytes, and are then fertilized. GLP-1 protein (in red) is expressed in mitotic germ cells and in anterior cells of the early embryo, but glp-1 mRNA is found throughout (blue lines). (B) Schematic of the glp-1 3' UTR and a chimeric unc-54 3' UTR used in lacZ reporter mRNAs. lacZ coding sequences include a nuclear localization signal. (C) Whole mount of a hermaphrodite injected with lacunc mRNA (no glp-1 sequences) and stained with X-gal. ß-gal activity (dark nuclear stain) was detected in the distal arm (arrows) and in oocyte nuclei (arrowheads), and weakly in embryos (asterisks). The site of injection is indicated by the large arrow. Injected lacZ mRNAs are typically excluded from the distal tip region for unknown reasons (data not shown). (D) A whole mount of a hermaphrodite injected with lacunc(34WT) mRNA. ß-gal activity was not detected in the distal arm (arrows) or in oocytes (arrowheads), but was strongly detected in embryos older than the 4-cell stage (asterisks). (E) An 8-cell embryo from an animal injected with lacunc(34WT) mRNA stained with X-gal and DAPI. Dark ß-gal staining was seen in the four anterior (AB) nuclei; one AB nucleus is not in focus. Staining was not detected or was very weak in four posterior cells (small arrowheads). (F) Whole mount hermaphrodite injected with lacunc(34LS1) mRNA which contains a mutation in the GRE of the SCR (see Fig. 2). Staining was detected in the distal arm (large arrow), near the gonad bend (small arrow), in oocytes (arrowheads), and in some older embryos (not shown).