title: The Potorous CPD photolyase rescues a cryptochrome-deficient mammalian circadian clock.
abstract: Despite the sequence and structural conservation between cryptochromes and photolyases, members of the cryptochrome/photolyase (flavo)protein family, their functions are divergent. Whereas photolyases are DNA repair enzymes that use visible light to lesion-specifically remove UV-induced DNA damage, cryptochromes act as photoreceptors and circadian clock proteins. To address the functional diversity of cryptochromes and photolyases, we investigated the effect of ectopically expressed Arabidopsis thaliana (6-4)PP photolyase and Potorous tridactylus CPD-photolyase (close and distant relatives of mammalian cryptochromes, respectively), on the performance of the mammalian cryptochromes in the mammalian circadian clock. Using photolyase transgenic mice, we show that Potorous CPD-photolyase affects the clock by shortening the period of behavioral rhythms. Furthermore, constitutively expressed CPD-photolyase is shown to reduce the amplitude of circadian oscillations in cultured cells and to inhibit CLOCK/BMAL1 driven transcription by interacting with CLOCK. Importantly, we show that Potorous CPD-photolyase can restore the molecular oscillator in the liver of (clock-deficient) Cry1/Cry2 double knockout mice. These data demonstrate that a photolyase can act as a true cryptochrome. These findings shed new light on the importance of the core structure of mammalian cryptochromes in relation to its function in the circadian clock and contribute to our further understanding of the evolution of the cryptochrome/photolyase protein family.
authors.affiliation: Department of Genetics, Erasmus University Medical Center, Rotterdam, The Netherlands. i.chaves@erasmusmc.nl
authors.forename: Inês
authors.initials: I
authors.lastname: Chaves
authors.forename: Romana M
authors.initials: RM
authors.lastname: Nijman
authors.forename: Magdalena A
authors.initials: MA
authors.lastname: Biernat
authors.forename: Monika I
authors.initials: MI
authors.lastname: Bajek
authors.forename: Karl
authors.initials: K
authors.lastname: Brand
authors.forename: António Carvalho
authors.initials: AC
authors.lastname: da Silva
authors.forename: Shoko
authors.initials: S
authors.lastname: Saito
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Yagita
authors.forename: André P M
authors.initials: AP
authors.lastname: Eker
authors.forename: Gijsbertus T J
authors.initials: GT
authors.lastname: van der Horst
mesh_terms: D056930:ARNTL Transcription Factors / Q000235:genetics / Q000378:metabolism; D000818:Animals; D056926:CLOCK Proteins / Q000235:genetics / Q000378:metabolism; D019556:COS Cells; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D057906:Circadian Clocks / Q000235:genetics / Q000502:physiology*; D056931:Cryptochromes / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D004255:Deoxyribodipyrimidine Photo-Lyase / Q000235:genetics / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D015151:Immunoblotting; D008099:Liver / Q000378:metabolism; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D008163:Luminescent Measurements / Q000379:methods; D051379:Mice; D018345:Mice, Knockout; D008822:Mice, Transgenic; D041681:NIH 3T3 Cells; D048328:Potoroidae / Q000378:metabolism*; D011485:Protein Binding; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014162:Transfection
chemical_list: D056930:ARNTL Transcription Factors; C538961:Bmal1 protein, mouse; C538964:Cry1 protein, mouse; C538967:Cry2 protein, mouse; D056931:Cryptochromes; D008156:Luciferases; D056926:CLOCK Proteins; C538944:Clock protein, mouse; D004255:Deoxyribodipyrimidine Photo-Lyase