An Animal-Like Cryptochrome Controls the Sexual Cycle.

Cryptochromes are known as flavin-binding blue light receptors in bacteria, fungi, plants, and insects. The animal-like cryptochrome (aCRY) of the green alga has extended our view on cryptochromes, because it responds also to other wavelengths of the visible spectrum, including red light. Here, we have investigated if aCRY is involved in the regulation of the sexual life cycle of , which is controlled by blue and red light at the steps of gametogenesis along with its restoration and germination.

A Plant Cryptochrome Controls Key Features of the Circadian Clock and Its Life Cycle.

Cryptochromes are flavin-binding proteins that act as blue light receptors in bacteria, fungi, plants, and insects and are components of the circadian oscillator in mammals. Animal and plant cryptochromes are evolutionarily divergent, although the unicellular alga ( throughout) has both an animal-like cryptochrome and a plant cryptochrome (pCRY; formerly designated CPH1). Here, we show that the pCRY protein accumulates at night as part of a complex.

Novel interaction of two clock-relevant RNA-binding proteins C3 and XRN1 in Chlamydomonas reinhardtii.

The RNA-binding protein CHLAMY1 of the green alga Chlamydomonas reinhardtii consists of two subunits, named C1 and C3 that maintain the period and phase of the circadian clock. Here, we investigated if any of its subunits interact with other clock components involved in RNA metabolism. We found that C3, but not C1 strongly interacts with exoribonuclease XRN1 whose knockout results in low amplitude rhythms.

A flavin binding cryptochrome photoreceptor responds to both blue and red light in Chlamydomonas reinhardtii.

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.

How the green alga Chlamydomonas reinhardtii keeps time.

The unicellular green alga Chlamydomonas reinhardtii has two flagella and a primitive visual system, the eyespot apparatus, which allows the cell to phototax. About 40 years ago, it was shown that the circadian clock controls its phototactic movement. Since then, several circadian rhythms such as chemotaxis, cell division, UV sensitivity, adherence to glass, or starch metabolism have been characterized.