Visible light exposure activates the CYP-encoding gene cyp-14A5 in a genetic program in C. elegans.

A, Representative epifluorescence and brightfield images showing cyp-14A5p::GFP induction by visible light exposure (1500 Lux, 24 hrs), in synchronized young adults (24 hrs post L4). Scale bar: 50 µm. B, Bubble plot showing fold induction of cyp-14A5p::GFP as a function of light intensity (Lux) and duration (hours of light_dark indicated in Y axis). C, Schematic of cyp-14A5 transcriptional and translational GFP reporters. The translational reporter shows non-neuronal (indicated by arrows) induction of CYP-14A5::GFP by light (1500 Lux, 24 hrs). Scale bar: 50 µm. D, Volcano plot showing genes differentially regulated by light (1500 Lux, 24 hrs), with cyp-14A5 highlighted, in synchronized young adults (24 hrs post L4). E, Heat map of top-ranking visible light-regulated genes (top 30 including cyp-14A5).

Light induction of cyp-14A5p::GFP requires the transcription factors ZIP-2 and CEBP-2.

A, Representative epifluorescence images showing light-induced cyp-14A5p::GFP expression in lite-1 gur-3 double and atm-1 single loss-of-function mutants. Scale bar: 50 µm. B, Summary of RNAi screens identifying ZIP-2 and CEBP-2 as essential transcriptional regulators of light-induced cyp-14A5p::GFP expression. C, Representative epifluorescence images showing light-induced cyp-14A5p::GFP expression in wild type, zip-2 and cebp-2 loss-of-function mutants. Scale bar: 50 µm. D, Representative epifluorescence images showing light-induced cyp-14A5p::GFP expression and no light-induced irg-1p::GFP expression in wild type animals. Scale bar: 50 µm. E, Representative epifluorescence images showing light-induced cyp-14A5p::GFP expression unaffected by a UV shield. Scale bar: 50 µm. F, Representative epifluorescence images showing light-induced cyp-14A5p::GFP expression by red, green, blue LED light sources of equal intensities. Scale bar: 50 µm. G, Quantification of E and F. *** indicates P < 0.001, n.s., non-significant. H, Representative epifluorescence images showing light-induced cyp-14A5p::GFP expression unaffected in rpl-28p::zip-2uORF transgenic animals. Scale bar: 50 µm. I, Representative epifluorescence images showing light-induced cyp-14A5p::GFP expression abolished in eif-2alpha mutants. Scale bar: 50 µm. J, Schematic model for light-induced transition of zip-2 mRNA from translating uORF to mORF, leading to increased ZIP-2 and subsequent increased transcriptional cyp-14A5 expression in cooperation with CEBP-2. Other molecular players are omitted and uORF and mORF are separated for clarity.

Light promotes behavioral plasticity and memory consolidation via a ZIP-2/CYP axis in hypodermis.

A, Schematic of behavioral setup to test effects of dark/light on olfactory memory. B, Wild-type learning and memory after 16 hours of dark exposure. 7 trials, 50-200 animals per trial/condition. Two-way ANOVA shows significant differences in chemotaxis (CI) under ambient light conditions (approximately 600 Lux) but not when the assay plates were placed in the dark. Learning (LI) indices reflect the differences between buffer- and butanone-treated animals, attenuated under dark (one-way ANOVA). Pairwise t-tests of the amount of memory retention under light and dark recovery reveal the degree of memory loss under dark. C, Dark exposure timeline shows that exposing animals to dark immediately after training (0-2 hr, Dark) hampered memory retention, whereas dark conditions for the 2–4-hour period is less sufficient to induce memory loss (two-way ANOVA). The lack of differences between buffer and butanone-trained animals is reflected in the respective LIs (one-way ANOVA). D, Two different loss-of-function alleles of zip-2(tm4246) or zip-2(ok3730) both showed impaired memory, but learning remained intact (two-way ANOVA). 5-10 trials, 50-200 animals per trial/condition. E, Memory impairment of cyp-14A5(gk152) but not F43C1.7 null mutant animals (two-way ANOVA for CIs and One-way ANOVA for LIs. 7-14 trials, 50-200 animals per trial/condition. F, Memory defects of cyp-14A5(gk152) mutants are rescued by hypodermal expression of wild-type cyp-14A5. Two independent transgenic lines show similar results with comparison of pairwise differences in LIs and the amount of memory rescued by hypodermal cyp-14A5 (Cis: Two-way ANOVA; Lis: One-way ANOVA). * indicates P < 0.05, ** indicates P < 0.01, *** indicates P < 0.001, **** indicates P < 0.0001, n.s., non-significant.

Light-induced gene expression drives organismal phenotypes, including sleep and shortened lifespans.

A, Schematic of synthetic constructs for light-inducible nlp-22 and zip-10::mCherry using the cyp-14A5 promoter. B, Representative compound epifluorescence images showing light-induced cyp-14A5p::zip-10::mCherry activation. Scale bar: 50 µm. Pharyngeal muscle-specific myo-2p::mCherry was used as a co-injection marker. C, Representative confocal fluorescence images showing light-induced cyp-14A5p::zip-10::mCherry activation (1500 Lux, 24 hrs starting at 24 hrs post L4) in major non-neuronal tissues (hypoderm, intestinal cells indicated by arrows). Scale bar: 50 µm. D, Representative lifespan curves showing that light-induced zip-10 can markedly shorten lifespan through transient light exposure (1500 Lux, 24 hrs starting at 24 hrs post L4). **** indicates P < 0.0001. E, Representative bright field images showing quiescent sleep behaviors by light-induced cyp-14A5p::nlp-22 expression through transient light exposure (1500 Lux, 24 hrs starting at 24 hrs post L4). F, Quantification of population bending frequencies for transient light-treated (1500 Lux, 24 hrs starting at 24 hrs post L4) control wild type and cyp-14A5p::nlp-22 animals. G, Quantification of population track lengths for control wild type and cyp-14A5p::nlp-22 animals with transient light (1500 Lux, 24 hrs starting at 24 hrs post L4) or darkness treatments. *** indicates P < 0.001, **** indicates P < 0.0001, n.s., non-significant.

cyp-14A5p::GFP induction responds primarily to visible light exposure rather than changes in ambient oxygen, nutrient or temperature.

A, Schematic of the setup for measurements of light intensity and temperature at a plane (in parallel to LED visible light sources) where animals are exposed to LED light in NGM plates. B, Measurements of temperature at the 600 Lux light intensity showing no change of temperature over 24 hrs. C, Measurements of temperature at the 1500 Lux light intensity showing no change of temperature over 24 hrs. D, Measurements of temperature at the 3000 Lux light intensity showing no change of temperature over 24 hrs. E-H, Representative bright-field and epifluorescence images showing no apparent cyp-14A5p::GFP induction by transient exposure to heat shock (F), constant exposure to 24 hrs of hypoxia (G) or starvation (H). Scale bar: 50 µm.

Gene ontology analysis of light-induced transcriptomic changes.

A, Starburst plot of gene ontology analysis of light-induced genes using WormCat (http://www.wormcat.com/). B, Table summary of gene ontology analysis of light-induced genes using WormEnrichr (https://maayanlab.cloud/WormEnrichr/).

No apparent effects of short-term transient visible LED light exposure on development, morphology, simple behaviors and lifespans.

A, Representative bright-field images showing no apparent effects of visible light exposure (1500 Lux, 24 hrs) on the body lengths and gross morphology of wild type, cebp-2, and zip-2 loss-of-function mutants. Scale bar: 50 µm. B. Representative images showing the movement tracks of wild type, cyp-14A5, and zip-2 loss-of-function mutants under dark and light (1500 Lux, 24 hrs) conditions. C, Quantification of track lengths of wild type, cyp-14A5, and zip-2 loss-of-function mutants under dark and light (1500 Lux, 24 hrs) conditions. D, Quantification of pumping rates of wild type, cyp-14A5, and zip-2 loss-of-function mutants under dark and light (1500 Lux, 24 hrs) conditions. E, Quantification of defecation behaviors of wild type, cyp-14A5, and zip-2 loss-of-function mutants under dark and light (1500 Lux, 24 hrs) conditions. F, Lifespan curves of wild-type animals under conditions of dark or transient LED light exposure for various indicated durations.

WormLab analysis reveals sleep bouts caused by light-induced cyp-14A5p::nlp-22 expression.

(A) Representative tracking of moving angles for body posture and average speed for control animals under dark conditions (N=15). (B) Representative tracking of moving angles for body posture and average speed for control animals after light exposure conditions (1500 Lux, 24 hrs, N=13). (C) Representative tracking of moving angles for body posture and average speed for cyp-14A5p::nlp-22 transgenic animals under dark conditions (N=12). (B) Representative tracking of moving angles for body posture and average speed for cyp-14A5p::nlp-22 transgenic animals after light exposure conditions (1500 Lux, 24 hrs, N=13).