Figure 2.
elt-4 is expressed in all cells of the intestine plus nine cells in the posterior pharynx.(A) Schematic representation of the three reporter gene fusions used to determine the
elt-4 expression pattern. At the top the
elt-4/elt-2 locus is shown, with scale centered on the initiation codon of
elt-4. The three constructs are: pJM401, in which 5.5 kb of the
elt-4 5'-flanking region are fused to GFP immediately after the
elt-4 ATG codon; pJM156, in which 6.8 kb of the
elt-4 5'-flanking region plus the
elt-4 coding region are fused to GFP immediately before the
elt-4 termination codon; and pJM188, a construct whose 11.2-kb insert contains 4.5 kb of the
elt-4 5'-flanking region, the entire
elt-4 coding region, the region between
elt-4 and
elt-2 (which includes the
elt-2 enhancer), and approximately half of the
elt-2 coding region (but not including the
elt-2 DNA-binding domain), into which a GFP coding sequence has been inserted immediately before the
elt-4 termination codon. (B) GFP fluorescence observed in embryos transformed with pJM188. B1, differential interference contrast (DIC) optics; B2, GFP fluorescence. Two embryos are at the 1.5-fold stage and two embryos are at the 3-fold stage. GFP expression is detected in all gut nuclei. Fluorescent images represent a maximum point projection of an aligned stack of nine deconvolved images taken at focal planes spaced at 1-um intervals. Bar, 20 um. (C) GFP fluorescence observed in an L1 larva transformed with pJM188. C1, DIC; C2, GFP fluorescence. GFP expression is detected in all nuclei of the intestine plus nine nuclei in the posterior bulb of the pharynx (arrow). Bar, 20 um. (D) Pharynx of an adult worm transformed with pJM188. D1, DIC; D2, GFP fluorescence. Fluorescent images represent a maximum point projection of an aligned stack of 15 deconvolved images taken at focal planes spaced at 1-um intervals. A full through-focus series reveals nine expressing nuclei (see text). Bar, 10 um.