title: A flavin binding cryptochrome photoreceptor responds to both blue and red light in Chlamydomonas reinhardtii.
abstract: Cryptochromes are flavoproteins that act as sensory blue light receptors in insects, plants, fungi, and bacteria. We have investigated a cryptochrome from the green alga Chlamydomonas reinhardtii with sequence homology to animal cryptochromes and (6-4) photolyases. In response to blue and red light exposure, this animal-like cryptochrome (aCRY) alters the light-dependent expression of various genes encoding proteins involved in chlorophyll and carotenoid biosynthesis, light-harvesting complexes, nitrogen metabolism, cell cycle control, and the circadian clock. Additionally, exposure to yellow but not far-red light leads to comparable increases in the expression of specific genes; this expression is significantly reduced in an acry insertional mutant. These in vivo effects are congruent with in vitro data showing that blue, yellow, and red light, but not far-red light, are absorbed by the neutral radical state of flavin in aCRY. The aCRY neutral radical is formed following blue light absorption of the oxidized flavin. Red illumination leads to conversion to the fully reduced state. Our data suggest that aCRY is a functionally important blue and red light-activated flavoprotein. The broad spectral response implies that the neutral radical state functions as a dark form in aCRY and expands the paradigm of flavoproteins and cryptochromes as blue light sensors to include other light qualities.
authors: Institute of General Botany and Plant Physiology, Friedrich Schiller University, 07743 Jena, Germany.
authors: Benedikt
authors: B
authors: Beel
authors: Katja
authors: K
authors: Prager
authors: Meike
authors: M
authors: Spexard
authors: Severin
authors: S
authors: Sasso
authors: Daniel
authors: D
authors: Weiss
authors: Nico
authors: N
authors: Müller
authors: Mark
authors: M
authors: Heinnickel
authors: David
authors: D
authors: Dewez
authors: Danielle
authors: D
authors: Ikoma
authors: Arthur R
authors: AR
authors: Grossman
authors: Tilman
authors: T
authors: Kottke
authors: Maria
authors: M
authors: Mittag
mesh_terms: D002453:Cell Cycle; D016825:Chlamydomonas reinhardtii / Q000235:genetics / Q000378:metabolism* / Q000528:radiation effects; D002734:Chlorophyll / Q000378:metabolism; D057906:Circadian Clocks; D002940:Circadian Rhythm; D056931:Cryptochromes / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D005415:Flavins / Q000378:metabolism; D005816:Genetic Complementation Test; D008027:Light; D016254:Mutagenesis, Insertional; D010084:Oxidation-Reduction; D055519:Photoreceptors, Plant / Q000235:genetics / Q000378:metabolism; D010802:Phylogeny; D030821:Plants, Genetically Modified; D019076:Transgenes
chemical_list: D056931:Cryptochromes; D005415:Flavins; D055519:Photoreceptors, Plant; D002734:Chlorophyll