A cryptochrome/photolyase class of enzymes with single-stranded DNA-specific photolyase activity

Selby, Christopher P.; Sancar, Aziz

doi:10.1073/pnas.0607993103

Cited by 274 publications

(298 citation statements)

References 29 publications

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“…In agreement with our data, it has recently been shown for other proteins of the Cry-DASH protein family from bacterial, plant, and animal sources that they are actually photolyases with a high degree of specificity for cyclobutane pyrimidine dimers in single-stranded DNA. The CRY-DASH photolyase activity in general seems to be weaker in comparison with the photolyase activities of CPD photolyases (Selby and Sancar, 2006). The additional cryptochrome-like regulatory function of a photolyase is a novelty for this class of proteins.…”

Section: Discussionmentioning

confidence: 96%

“…Cryptochromes are characterized by an N-terminal photolyase-related (PHR) region without significant photorepair activity and by a C-terminal domain of varying length, which is absent in members of the CRY-DASH subfamily (Daiyasu et al, 2004). The exact function of the CRY-DASH proteins was elusive; however, recent data imply that they are actually photolyases that specifically repair CPDs in single-stranded DNA (Selby and Sancar, 2006). The PHR domain is the most conserved region of the CRY proteins and contains the cofactor FAD required for electron transfer reactions.…”

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confidence: 99%

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More Than a Repair Enzyme:Aspergillus nidulansPhotolyase-like CryA Is a Regulator of Sexual Development

Bayram

Biesemann

Krappmann

et al. 2008

MBoC

129

116

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Cryptochromes are blue-light receptors that have presumably evolved from the DNA photolyase protein family, and the genomes of many organisms contain genes for both types of molecules. Both protein structures resemble each other, which suggests that light control and light protection share a common ancient origin. In the genome of the filamentous fungus Aspergillus nidulans, however, only one cryptochrome/photolyase-encoding gene, termed cryA, was identified. Deletion of the cryA gene triggers sexual differentiation under inappropriate culture conditions and results in upregulation of transcripts encoding regulators of fruiting body formation. CryA is a protein whose N-and C-terminal synthetic green fluorescent protein fusions localize to the nucleus. CryA represses sexual development under UVA 350-370 nm light both on plates and in submerged culture. Strikingly, CryA exhibits photorepair activity as demonstrated by heterologous complementation of a DNA repair-deficient Escherichia coli strain as well as overexpression in an A. nidulans uvsB⌬ genetic background. This is in contrast to the single deletion cryA⌬ strain, which does not show increased sensitivity toward UV-induced damage. In A. nidulans, cryA encodes a novel type of cryptochrome/photolyase that exhibits a regulatory function during light-dependent development and DNA repair activity. This represents a paradigm for the evolutionary transition between photolyases and cryptochromes. INTRODUCTIONCryptochromes (CRYs) are blue-light receptors that regulate growth, development, and the circadian clock in higher eukaryotes and that are believed to have evolved from the DNA photolyase protein family (Daiyasu et al., 2004;Lin and Todo, 2005). Photolyases, in contrast, repair UV-induced DNA damage by using a mechanism referred to as photorepair. They absorb light in the blue spectrum and transfer an excited electron from the cofactor FAD to an enzyme-bound cyclobutane pyrimidine dimer (CPD), which is thereby cleaved (Sancar, 1990(Sancar, , 1994Sancar, 1994). Cryptochromes are characterized by an N-terminal photolyase-related (PHR) region without significant photorepair activity and by a C-terminal domain of varying length, which is absent in members of the CRY-DASH subfamily (Daiyasu et al., 2004). The exact function of the CRY-DASH proteins was elusive; however, recent data imply that they are actually photolyases that specifically repair CPDs in single-stranded DNA (Selby and Sancar, 2006). The PHR domain is the most conserved region of the CRY proteins and contains the cofactor FAD required for electron transfer reactions. In Xenopus and Drosophila, the PHR domain is physiologically active even in the absence of the C-terminal domain. The C-terminal domain is important for either localization or protein stability, and its expression in Arabidopsis results in constitutive growth (Lin and Todo, 2005). Plant CRYs are phosphorylated under illumination, and gene expression control ranges from protein interactions to direct chromatin interactions (Shalitin et al....

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Section: Discussionmentioning

confidence: 96%

mentioning

confidence: 99%

More Than a Repair Enzyme:Aspergillus nidulansPhotolyase-like CryA Is a Regulator of Sexual Development

Bayram

Biesemann

Krappmann

et al. 2008

MBoC

129

116

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“…When this strain was complemented, illumination increased the survival to 67 %, similar to that of the complemented phrA mutant. Selby & Sancar (2006) reported recently that members of the previously found cryptochrome DASH family (Brudler et al, 2003;Daiyasu et al, 2004) repair single stranded DNA. Although RSP3077 shows only minor (up to 9 %) sequence identity to members of this family, we can not exclude a function of RSP3077 in this regard and a role as putative second photolyase.…”

Section: Resultsmentioning

confidence: 99%

“…The recently identified cryptochrome Drosophila, Arabidopsis, Synechocystis, Human (cryptochrome DASH) proteins lack the C-terminal extension. This group was found to specifically repair CPDs in single-stranded DNA (Selby & Sancar, 2006) and its members are therefore considered to be photolyases.…”

Section: Introductionmentioning

confidence: 99%

The phrA gene of Rhodobacter sphaeroides encodes a photolyase and is regulated by singlet oxygen and peroxide in a σ E-dependent manner

et al. 2007

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“…Photolyases are known to utilize two-electron reduced deprotonated flavin (FADH -) as the native cofactor (Sancar 2003;Selby and Sancar 2006); however, when purified under aerobic conditions, they may have the flavin in any of the three oxidation states, FADH -, FADH°(blue neutral radical), and FAD ox (Sancar 2003). Hence, it is not possible to ascertain the redox status of the cofactor in vivo by inspecting the redox status of the flavin cofactor of purified photolyase.…”

Section: Physical Propertiesmentioning

confidence: 99%

Structure and Function of Animal Cryptochromes

Öztürk

Song²,

Özgür³

et al. 2007

Cold Spring Harbor Symposia on Quantitative Biology

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Cryptochrome (CRY) is a photolyase-like flavoprotein with no DNA-repair activity but with known or presumed blue-light receptor function. Animal CRYs have DNA-binding and autokinase activities, and their flavin cofactor is reduced by photoinduced electron transfer. In Drosophila, CRY is a major circadian photoreceptor, and in mammals, the two CRY proteins are core components of the molecular clock and potential circadian photoreceptors. In mammals, CRYs participate in cell cycle regulation and the cellular response to DNA damage by controlling the expression of some cell cycle genes and by directly interacting with checkpoint proteins. in response to blue light (Koornneef et al. 1980), was isolated and sequenced, it revealed high sequence homology with Escherichia coli photolyase, and hence, it was in retrospect, correctly speculated that HY4 encoded a blue light photoreceptor and not a signal transducer involved in blue light response (Ahmad and Cashmore 1993). Later, this protein was named cryptochrome 1 (Lin et al. 1995, and a second Arabidopsis protein that has high homology with CRY1 identified by genomics was named CRY2 . The role of CRY in Arabidopsis growth (CRY1) and differentiation (CRY2) was well established by 1995 (see Guo et al. 1998). However, as late as 1997, it was thought that CRY had no role in circadian photoreception in plants (Millar and Kay 1997).The first report implicating CRY in the circadian clock of any organism, plant or animal, came about from the study of DNA repair, in particular, the repair of UV damage in humans by photolyase. This issue had been controversial for nearly 25 years when Li et al. (1993) conducted an exhaustive study with a highly specific and sensitive assay, concluding that humans, like all placental mammals, lacked photolyase (Li et al. 1993). However, a 1995 release of a human expressed sequence tag (EST) list contained a "photolyase ortholog" entry (Adams et al. 1995). In light of this finding and the discovery of a photolyase in Drosophila and rattlesnake (Todo et al. 1993Kim et al. 1996) that repairs the minor UV-induced lesion, the (6-4) photoproduct, in contrast to the classic photolyase that repairs cyclobutane pyrimidine dimers (CPDs), the earlier conclusion regarding the lack of photolyase in humans needed reevaluation. This was done by Hsu et al. (1996) who, in addition to the "photolyase ortholog" in public databases, discovered a second human photolyase gene. Human cells expressing both genes and recombinant proteins encoded by both genes were tested for CPD and (6-4) photolyase activities and were found to lack both. Moreover, the proteins encoded by these genes, like most photolyases (Johnson et al. 1988) and Arabidopsis CRY (Lin et al. 1995; Malhorta et al. 1995), contained FAD (flavin-adenine dinucleotide) and a pterin cofactor. Therefore, it was concluded that these proteins were not repair enzymes but that, like Arabidopsis CRYs, they performed non-repair-related blue light functions and were named human CRY1 and 2 (Hsu et al. 1996). In humans ...

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A cryptochrome/photolyase class of enzymes with single-stranded DNA-specific photolyase activity

Cited by 274 publications

References 29 publications

More Than a Repair Enzyme:Aspergillus nidulansPhotolyase-like CryA Is a Regulator of Sexual Development

More Than a Repair Enzyme:Aspergillus nidulansPhotolyase-like CryA Is a Regulator of Sexual Development

The phrA gene of Rhodobacter sphaeroides encodes a photolyase and is regulated by singlet oxygen and peroxide in a σ E-dependent manner

Structure and Function of Animal Cryptochromes

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