期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2015
卷号：112
期号：49
页码：15130-15135
DOI：10.1073/pnas.1514637112
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：SignificancePhotolyases repair UV-B-induced DNA lesions. They form a large protein family together with cryptochrome photoreceptors (cryptochrome/photolyase family, CPF). A more recently discovered CPF subclade consists of DASH (Drosophila, Arabidopsis, Synechocystis, Human)-type cryptochromes (cry-DASH), present in bacteria, plants, animals, and fungi. Cry-DASH are considered as photoreceptors with residual repair activity for DNA lesions in single-stranded DNA. Canonical photolyases repair such lesions in single-stranded and double-stranded DNA. Here, we show that mucoromycotina fungi except Umbelopsis ramanniana, which is an early diverging lineage within the mucoralean fungi, encode only cry-DASH. They possess the full spectrum of DNA repair activity as canonical photolyases as exemplified for the Phycomyces CryA. This finding is a unique example of CPF evolution where a canonical CPD-photolyase was lost but its function was maintained by cry-DASH. DASH (Drosophila, Arabidopsis, Synechocystis, Human)-type cryptochromes (cry-DASH) belong to a family of flavoproteins acting as repair enzymes for UV-B-induced DNA lesions (photolyases) or as UV-A/blue light photoreceptors (cryptochromes). They are present in plants, bacteria, various vertebrates, and fungi and were originally considered as sensory photoreceptors because of their incapability to repair cyclobutane pyrimidine dimer (CPD) lesions in duplex DNA. However, cry-DASH can repair CPDs in single-stranded DNA, but their role in DNA repair in vivo remains to be clarified. The genome of the fungus Phycomyces blakesleeanus contains a single gene for a protein of the cryptochrome/photolyase family (CPF) encoding a cry-DASH, cryA, despite its ability to photoreactivate. Here, we show that cryA expression is induced by blue light in a Mad complex-dependent manner. Moreover, we demonstrate that CryA is capable of binding flavin (FAD) and methenyltetrahydrofolate (MTHF), fully complements the Escherichia coli photolyase mutant and repairs in vitro CPD lesions in single-stranded and double-stranded DNA with the same efficiency. These results support a role for Phycomyces cry-DASH as a photolyase and suggest a similar role for cry-DASH in mucoromycotina fungi.
