observation-of-photobehavior-in-chlamydomonas-reinhardtii

Observation of Photobehavior in <em>Chlamydomonas reinhardtii</em>

For the survival of the motile phototrophic microorganisms, being under proper light conditions is crucial. Consequently, they show photo-induced ...

Tokyo Institute of Technology

Light-responsive regulation of ciliary motility is known to be conducted through modulation of dyneins, but the mechanism is not fully understood. Here, we report a novel subunit of the two-headed f/I1 inner arm dynein, named DYBLUP, in animal spermatozoa and a unicellular green alga. This subunit contains a BLUF (sensors of blue light using FAD) domain that appears to directly modulate dynein activity in response to light. DYBLUP (dynein-associated BLUF protein) mediates the connection between the f/I1 motor domain and the tether complex that links the motor to the doublet microtubule.  lacking the DYBLUP ortholog shows both positive and negative phototaxis but becomes acclimated and attracted to high-intensity blue light. These results suggest a mechanism to avoid toxic strong light via direct photoregulation of dyneins.

A dynein-associated photoreceptor protein prevents ciliary acclimation to blue light.

Reactive oxygen species (ROS) can both act as a poison causing cell death and important signaling molecules among various organisms. Photosynthetic organisms inevitably produce ROS, making the appropriate elimination of ROS an essential strategy for survival. Interestingly, the unicellular green alga Chlamydomonas reinhardtii expresses a mammalian form of thioredoxin reductase, TR1, which functions as a ROS scavenger in animal cells. To investigate the properties of TR1 in C. reinhardtii, we generated TR1 knockout strains using CRISPR/Cas9-based genome editing. We found a reduced tolerance to high-light and ROS stresses in the TR1 knockout strains compared to the parental strain. In addition, the regulation of phototactic orientation, known to be regulated by ROS, was affected in the knockout strains. These results suggest that TR1 contributes to a ROS-scavenging pathway in C. reinhardtii.

Article	Year
A dynein-associated photoreceptor protein prevents ciliary acclimation to blue light. Science advances\| PubMed ID: 33637535	2021
The mammalian-type thioredoxin reductase 1 confers a high-light tolerance to the green alga Chlamydomonas reinhardtii. Biochemical and biophysical research communications\| PubMed ID: 35121375	2022

Yuma Asahina

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