What is period and Cryptochrome?

Expression of the two other key circadian proteins—Period and Cryptochrome—is switched on by CLOCK and BMAL1. As Period and Cryptochrome proteins accumulate, they begin to inhibit the activity of CLOCK and BMAL1, helping to reduce the rate at which the circadian genes are transcribed as the day progresses.

What is the function of cryptochrome?

Cryptochromes are photoreceptors that regulate entrainment by light of the circadian clock in plants and animals. They also act as integral parts of the central circadian oscillator in animal brains and as receptors controlling photomorphogenesis in response to blue or ultraviolet (UV-A) light in plants.

What is a Cryptochrome in biology?

Cryptochromes (from the Greek κρυπτός χρώμα, “hidden colour”) are a class of flavoproteins found in plants and animals that are sensitive to blue light. They are involved in the circadian rhythms and the sensing of magnetic fields in a number of species.

How are cryptochromes related to the circadian clock?

In Drosophila, cryptochrome (dCRY) acts as a blue-light photoreceptor that directly modulates light input into the circadian clock, while in mammals, cryptochromes (CRY1 and CRY2) act as transcription repressors within the circadian clockwork.

What do you need to know about circadian rhythms?

What are circadian rhythms? Circadian rhythms are physical, mental, and behavioral changes that follow a 24-hour cycle. These natural processes respond primarily to light and dark and affect most living things, including animals, plants, and microbes.

How does cry affect the circadian clock in Drosophila?

Cry mutants have altered circadian rhythms, showing that Cry affects the circadian pacemaker. Drosophila with mutated Cry exhibit little to no mRNA cycling. A point mutation in cryb, which is required for flavin association in CRY protein, results in no PER or TIM protein cycling in either DD or LD.

Where is the circadian clock located in a mammal?

In mammals. The primary circadian clock in mammals is located in the suprachiasmatic nucleus (or nuclei) (SCN), a pair of distinct groups of cells located in the hypothalamus. Destruction of the SCN results in the complete absence of a regular sleep–wake rhythm. The SCN receives information about illumination through the eyes.