# UV to blue neuronal phototransduction mechanisms

> **NIH NIH R35** · UNIVERSITY OF CALIFORNIA-IRVINE · 2024 · $46,940

## Abstract

Abstract of Awarded Parent Grant R35 GM127102, NOT-GM-24-021 Supplement Request
 Many insects pose major health and economic hazards to humans as common disease
vectors and agricultural pests. Almost all of our present understanding of insect
phototransduction is based on opsin-based photoreception in eyes that mediate image forming
vision. My lab has recently discovered two additional phototransduction mechanisms in
Drosophila. Cryptochrome (CRY) and Rhodopsin 7 (Rh7) expressed in central brain neurons
mediate rapid onset sustained electrophysiological responses in these neurons. CRY and Rh7
light signaling underlie a novel form of non-image forming vision that strongly modulates complex
time-of-day dependent insect behavioral responses to light, including avoidance/attraction
behavioral choice between light and shade and light evoked arousal. While CRY’s mechanism
of action is due to light evoked redox state changes of its flavin adenine dinucleotide (FAD)
chromophore and Rh7’s mechanism of action is through a G-protein signaling pathway, they
physiologically interact and may form the basis of a true color vision system for non-image forming
vision that discerns specific light spectra. We have extended our study of non-image forming
vision to harmful nocturnal Anopheles gambiae and diurnal Aedes aegypti mosquitoes and find
that CRY1s mediate very distinct time-of-day dependent species specific behavioral light
responses in these mosquitp-o important disease vectors. Remarkably, nocturnal and diurnal
mosquito CRY1s confer mosquito species specific behavioral effects when expressed in all CRY
expressing cells in a cry-null Drosophila genetic background and nocturnal mosquito CRY1 is
significantly more light sensitive than diurnal mosquito CRY1 measured by multiple behavioral
and electrophysiological assays. We will determine the detailed mechanisms that confer species
specific physiological and behavioral light responses for flies and mosquitoes and other insects
using a highly sensitive electrophysiological assay that we have developed that will allow us to
accurately measure redox state changes and biological outputs for light sensitive CRYs and
functional interactions between CRYs and Rh7, in combination with behavioral analysis. Our
custom designed instrumentation allows us to examine CRY spectrally driven redox state
changes in vivo. Present insect control strategies rely heavily on highly toxic pesticides. A far
more environmentally friendly alternative is to make use of light-based behavioral manipulation of
insects in a species specific fashion to attract harmful insect species to traps or to repel them
away from human habitation. The goal of our research to form a rational basis for designing
innovative new LED devices for species-specific harmful insect control in the ongoing fight against
vector-borne diseases.

## Key facts

- **NIH application ID:** 11034349
- **Project number:** 3R35GM127102-07S1
- **Recipient organization:** UNIVERSITY OF CALIFORNIA-IRVINE
- **Principal Investigator:** Todd C Holmes
- **Activity code:** R35 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $46,940
- **Award type:** 3
- **Project period:** 2018-04-01 → 2028-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/11034349

## Citation

> US National Institutes of Health, RePORTER application 11034349, UV to blue neuronal phototransduction mechanisms (3R35GM127102-07S1). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/11034349. Licensed CC0.

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