Re-configuring O₂ sensing circuits by altering the <i>npr-1</i> and <i>glb-5</i> genes alters CO₂ avoidance behavior.

Abstract

<p>A. Tuning of CO₂ avoidance behavior by different O₂ concentrations in N2 (Bristol), CB4856 (Hawaiian), <i>npr-1(ad609)</i>, <i>glb-5(Haw)</i>; <i>npr-1(ad609)</i>, and <i>glb-5(Haw)</i> animals. All assays used a 1–0% CO₂ gradient. Statistical comparisons are to the N2 response at the corresponding O₂ concentration, *** <i>p</i><0.001; ** <i>p</i><0.01; *<i>p</i><0.05 (Anova, <i>p</i> value protected Fisher's LSD). B. <i>gcy-35</i> and <i>gcy-36</i> mutants strongly avoid CO₂ regardless of genotype at the <i>npr-1</i> locus. Statistical comparisons are to the <i>npr-1</i> response at the corresponding O₂ concentration. ***, <i>p</i><0.001, **, <i>p</i><0.01, Anova, Bonferroni corrected <i>p</i> value). C. CB4856 (Hawaii) animals defective in <i>gcy-36</i> strongly avoid CO₂ regardless of O₂ levels. Statistical comparisons are to the CB4856 response at the corresponding O₂ concentration. ***, <i>p</i><0.001, **, <i>p</i><0.01, Anova, Bonferroni corrected <i>p</i> value). D, E. Tonic Ca²⁺ levels in URX neurons of <i>glb-5(Haw); npr-1</i> animals kept at 21% O₂ and 17% O₂ is lower than Ca²⁺ levels in URX in <i>npr-1</i> animals kept at the corresponding O₂ concentrations. Ca²⁺ measurements were made using cameleon YC2.60.</p