DOI: 10.5061/dryad.kd51c5bdk
title: Hypoxia-inducible factor induces cysteine dioxygenase and promotes cysteine homeostasis in Caenorhabditis elegans

description: Dedicated genetic pathways regulate cysteine homeostasis. For example,
 high levels of cysteine activate cysteine dioxygenase, a key enzyme in
 cysteine catabolism in most animal and many fungal species. The mechanism
 by which cysteine dioxygenase is regulated is largely unknown. In an
 unbiased genetic screen for mutations that activate cysteine dioxygenase
 (cdo-1) in the nematode C. elegans, we isolated
 loss-of-function mutations
 in rhy-1 and egl-9, which encode
 proteins that negatively regulate the stability or activity of the
 oxygen-sensing hypoxia-inducible transcription factor (hif-1). EGL-9 and
 HIF-1 are core members of the conserved eukaryotic hypoxia response.
 However, we demonstrate that the mechanism of HIF-1-mediated induction
 of cdo-1 is largely independent of EGL-9 prolyl
 hydroxylase activity and the von Hippel-Lindau E3 ubiquitin ligase, the
 classical hypoxia signaling pathway components. We demonstrate
 that C. elegans cdo-1 is transcriptionally activated by
 high levels of cysteine and hif-1. hif-1-dependent
 activation of cdo-1 occurs downstream of an H2S-sensing
 pathway that includes rhy-1,
 cysl-1, and egl-9. cdo-1 transcription
 is primarily activated in the hypodermis where it is also sufficient to
 drive sulfur amino acid metabolism. Thus, the regulation
 of cdo-1 by hif-1 reveals a negative
 feedback loop that maintains cysteine homeostasis. High levels of cysteine
 stimulate the production of an H2S signal. H2S then acts through
 the rhy-1/cysl-1/egl-9 signaling pathway to increase
 HIF-1-mediated transcription of cdo-1, promoting the
 degradation of cysteine via CDO-1.
description: All data is from fluorescence microscopy, <em>C.
 elegans</em> growth assays, or <em>C. elegans</em>
 survival assays.
description: # Hypoxia-inducible factor induces cysteine dioxygenase and promotes
 cysteine homeostasis in *Caenorhabditis elegans*
 All data is from
 fluorescence microscopy, *C. elegans* growth assays, or *C. elegans*
 survival assays. ## Description of the data and file structure Figures 1E,
 2B, 2C, 3B, 3C, and 5D represent Pcdo-1::GFP expression in *C. elegans*.
 Data are lists of mean GFP fluorescent values in a defined region of
 interest. Quantification was performed in FIJI and values are reported in
 arbitrary units. Genotypes and experimental conditions are displayed when
 appropriate. Figure 4- figure supplements 1B and 2B represent CDO-1::GFP
 expression in *C. elegans*. Data are lists of mean GFP fluorescent values
 in a defined region of interest. Quantification was performed in FIJI and
 values are reported in arbitrary units. Genotypes and experimental
 conditions are displayed when appropriate. Figures 4C, 4D, and Figure 1-
 figure supplement 1 represent the quantification of animal length in
 microns as measured from the tip of head to the end of tail after a set
 amount of time post-L1 stage of development. Measurements were performed
 in FIJI. Genotypes and experimental conditions are displayed when
 appropriate. Figure 3D, 3E, and 3F represent the percentage of animals
 surviving overnight exposure to 0 (3D), 100 (3E), or 1,000 (3F) micromolar
 supplemental cysteine. Genotypes and experimental conditions are displayed
 when appropriate. Table 1 data represent the number of days required for 5
 L4-staged animals to starve the E. coli food source under standard *C.
 elegans* culture conditions. Genotypes and experimental conditions are
 displayed when appropriate. Complete experimental details are available in
 the methods section of the associated manuscript: Hypoxia-inducible factor
 induces cysteine dioxygenase and promotes cysteine homeostasis in
 *Caenorhabditis elegans*.