2015-09-09

Background Photolyases and cryptochromes are evolutionarily related flavoproteins, which however perform distinct physiological functions. Photolyases (PHR) are evolutionarily ancient enzymes. They are activated by light and repair DNA damage caused by UV radiation. Although cryptochromes share structural similarity with DNA photolyases, they lack DNA repair activity. Cryptochrome (CRY) is one of the key elements of the circadian system in animals. In plants, CRY acts as a blue light receptor to entrain circadian rhythms, and mediates a variety of light responses, such as the regulation of flowering and seedling growth. Results We performed a comprehensive evolutionary analysis of the CRY/PHR superfamily. The superfamily consists of 7 major subfamilies: CPD class I and CPD class II photolyases, (6–4) photolyases, CRY-DASH, plant PHR2, plant CRY and animal CRY. Although the whole superfamily evolved primarily under strong purifying selection (average ω = 0.0168), some subfamilies did experience strong episodic positive selection during their evolution. Photolyases were lost in higher animals that suggests natural selection apparently became weaker in the late stage of evolutionary history. The evolutionary time estimates suggested that plant and animal CRYs evolved in the Neoproterozoic Era (~1000–541 Mya), which might be a result of adaptation to the major climate and global light regime changes occurred in that period of the Earth’s geological history.

Mei, Q, Dvornyk, V. (2015). Data from: Evolutionary History of the Photolyase/Cryptochrome Superfamily in Eukaryotes. [Data File]. All sequences are available from the Genbank database, please see supplementary S1 Table for accession numbers.
Click on “Linked Publications” to access the publication and access supporting information on figshare at https://figshare.com/articles/_Evolutionary_History_of_the_Photolyase_Cryptochrome_Superfamily_in_Eukaryotes_/1537962

DNA photolyases

seedling growth.ResultsWe

UV radiation

CRY acts

repair DNA damage

entrain circadian rhythms

superfamily

animal CRY

lack DNA repair activity

Evolutionary History

phr

light regime changes

light receptor

CPD class II photolyases

cryptochromes share

animal CRYs

light responses

circadian system

time estimates

Eukaryotes BackgroundPhotolyases

CPD class