Figure 3.—

Location of ot119 and ot201 and their effect on reporter gene expression. (A) Genomic region containing the cog-1 locus. Coordinates refer to base pairs on linkage group II. See Figure 2 for explanation of the stippled interval. Conserved ASE motifs are highlighted and numbers next to the sequence indicate positions relative to the ATG start codon of the longer cog-1 isoform. The nucleotides in blue are putative transcription-factor-binding sites linked to the ASE motifs; they occur in opposite orientation and differ in relative location to each ASE motif. Shaded boxes indicate 100% conservation between all species. Black lines indicate DNA injected into the respective mutant strain to test for rescue of the ASE mutant phenotype. (B) Alignment of the cog-1 ASE motif and its mutated versions in ot109 and ot201 animals to the ASE consensus motif. “ZF” indicate the zinc fingers of CHE-1 with which it contacts its cognate binding sequence (Etchberger et al. 2007). (C) Reporter constructs. “ASE expression” indicates expression in at least one (ASER) or two ASE cells expressing gfp; note that the apparent left/right asymmetric expression of this reporter gene is brought about by transcriptional autoregulation of the translationally controlled COG-1 protein (Johnston et al. 2005). Expression was scored in young adults in a otIs151 transgene background to allow identification of the ASE neurons. In the one case in which an intermediate level of penetrance was observed (promA-del2), the brightness of the gfp signal seemed to vary in those animals where expression is observed in ASE, compared to the wild-type construct where little of such variance was observed. More details on constructs can be found in the supplemental Materials and Methods. Constructs with an * have been described in Etchberger et al. (2007) and are shown for comparison only. (D) gfp images of three animals, each expressing the indicated cog-1 reporter gene fusion and a chromosomally integrated transgene, ceh-36∷dsRed2 (otIs151), used to label ASER. Images of the green and red channel of the same animal in the same position are merged in the last set of panels. Blue arrows indicate ASER.