TGF-β Signaling Mediates Food Suppression of Hyperoxia Avoidance

<p>(A–E), (H), (I) In all panels, dotted lines indicate aerotaxis in the presence of a small amount of bacterial food. (A) Aerotaxis of wild-type N2 animals. (B) Aerotaxis of <i>daf-7</i> mutants. (C) Aerotaxis of <i>daf-3</i> mutants. (D) Aerotaxis of <i>daf-7; daf-3</i> double mutants. (E) Aerotaxis of <i>daf-3 npr-1</i> double mutants. (F–G) <i>daf-7::GFP</i> expression in ASI was reduced in a <i>tax-4</i> mutant. Anterior is to the left. (H) Aerotaxis of <i>tax-4; kyIs342</i> animals, which bear a transgene that rescues <i>tax-4</i> in URX, AQR, and PQR, but not in ASI or other neurons. (I) Aerotaxis of <i>tph-1; daf-3</i> double mutants. For (A–E), (H), and (I), asterisks denote distributions different by chi-square analysis at <i>p</i> < 0.01 from the same genotype without food. <i>n</i> ≥ 3 assays per genotype and condition, 80–100 animals/assay. Error bars denote SEM. (J) Hyperoxia avoidance index as defined in <a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.0040274#pbio-0040274-g001" target="_blank">Figure 1</a>. Asterisks, values significantly different from the same genotype without food at <i>p</i> < 0.05 by <i>t</i> test. In the absence of food, no strain is different from N2 controls by Dunnett test. In the presence of food, <i>daf-7, daf-3 npr-1,</i> and <i>tph-1; daf-3</i> are different from N2 at <i>p <</i> 0.01 and <i>tax-4; kyIs342</i> different from N2 at <i>p</i> < 0.05 by Dunnett test. Error bars denote SEM.</p>