The Coevolution of Blue-Light Photoreception and Circadian Rhythms

Gehring, Walter; Rosbash, Michael

doi:10.1007/s00239-003-0038-8

Cited by 112 publications

(86 citation statements)

References 35 publications

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“…The identification of DNA-PK as a regulator of circadian period is interesting because of a long-recognized intimate relationship between DNA repair and circadian rhythms, and it may be that circadian clocks evolved as a protective mechanism to protect DNA from light-and radiation-induced damage (62). Furthermore, loss of various clock components, including CLOCK, BMAL1, PER1, and PER2, have been linked to increased chronic sensitivity to DNA cross-linking reagents, increased tumor development, and deficiencies in DNA damage responses (63)(64)(65).…”

Section: Discussionmentioning

confidence: 99%

Phosphorylation of the Cryptochrome 1 C-terminal Tail Regulates Circadian Period Length

Gao

Yoo

Lee

et al. 2013

Journal of Biological Chemistry

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Background: Cryptochromes (CRYs) are transcriptional repressors that are critical components of the circadian clock. Results: We have identified a phosphorylation site in the CRY1 tail that is negatively regulated by the DNA repair enzyme DNA-dependent protein kinase. Conclusion: Phosphorylation of CRY1 on Ser-588 increases its half-life and lengthens the circadian period. Significance: The C-terminal tail of CRY1 modulates period length.

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Section: Discussionmentioning

confidence: 99%

Phosphorylation of the Cryptochrome 1 C-terminal Tail Regulates Circadian Period Length

Gao

Yoo

Lee

et al. 2013

Journal of Biological Chemistry

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“…1), which repair UV-induced DNA damage by a photoinduced cyclic electron transfer reaction (Sancar 2003;Kao et al 2005). These two seemingly unrelated phenomena, circadian rhythm and DNA repair, may have had a common evolutionary origin (Pittendrigh 1993;Sancar 2000;Gehring and Rosbash 2003;Lowrey and Takahashi 2004). According to this "escape from light" hypothesis, in the distant past when more UV reached the surface of the earth, an aquatic organism used a blue-light photoreceptor (CRY) to restrict its S phase to the dark phase of the day (night) so as to minimize the harmful effects of DNA damage and to regulate the organism's vertical movement to and away from the surface of the water with daily (circadian) periodicity, thereby optimizing nutrient uptake and minimizing the extent of DNA damage.…”

Section: Introductionmentioning

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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“…Blue light plays a central role in the entrainment of circadian clocks. Indeed blue-light photoreceptors and circadian clocks may have coevolved from a mechanism that originally served to detect (photoreceptor) and avoid (timer) harmful radiation (4)(5)(6). Our understanding of the molecular bases of circadian clocks and their responses to light has improved dramatically during the last decade or so, and the eukaryotic model organism Neurospora crassa has become one of the best-studied systems for understanding both processes (7)(8)(9).…”

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confidence: 99%

VIVID interacts with the WHITE COLLAR complex and FREQUENCY-interacting RNA helicase to alter light and clock responses in Neurospora

Hunt

Thompson

Elvin

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

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The photoreceptor and PAS/LOV protein VIVID (VVD) modulates blue-light signaling and influences light and temperature responses of the circadian clock in Neurospora crassa. One of the main actions of VVD on the circadian clock is to influence circadian clock phase by regulating levels of the transcripts encoded by the central clock gene frequency (frq). How this regulation is achieved is unknown. Here we show that VVD interacts with complexes central for circadian clock and blue-light signaling, namely the WHITE-COLLAR complex (WCC) and FREQUENCY-interacting RNA helicase (FRH), a component that complexes with FRQ to mediate negative feedback control in Neurospora. VVD interacts with FRH in the absence of WCC and FRQ but does not seem to control the exosome-mediated negative feedback loop. Instead, VVD acts to modulate the transcriptional activity of the WCC.ight, in addition to providing an energy source for many life forms on Earth, acts as a signal that may trigger development or serve as a repetitive cue that marks the passing of external time. External time cues are used by cellular timers such as circadian clocks to lock their periods to that of the external day. The process of period locking is called "entrainment" and ensures that cellular and behavioral activities happen at times of day when their adaptive value is highest (1-3). Blue light plays a central role in the entrainment of circadian clocks. Indeed blue-light photoreceptors and circadian clocks may have coevolved from a mechanism that originally served to detect (photoreceptor) and avoid (timer) harmful radiation (4-6). Our understanding of the molecular bases of circadian clocks and their responses to light has improved dramatically during the last decade or so, and the eukaryotic model organism Neurospora crassa has become one of the best-studied systems for understanding both processes (7-9).The key components of the Neurospora circadian clock are the products of the white collar (wc-1 and wc-2), frequency (frq), and frq-interacting helicase (frh) genes (4, 10, 11). The blue-light photoreceptor WC-1, and its interaction partner WC-2, form the transcriptionally and photoactive WHITE COLLAR complex (WCC) that activates frq expression (4, 12). FRQ protein, in turn, complexes with FRH to form an FRQ-FRH complex (FFC) that represses WCC activity (9, 11). Thus, photoreception and temporal organization of gene expression are linked via the WCC (4,(12)(13)(14). Hyperphosphorylated WCC is transcriptionally less active, and repression of WCC by FRQ occurs via FRQ-mediated phosphorylation of WCC by Casein kinase 1 and 2 (CK1 and 2) (14, 15).A second feedback loop that acts to repress WCC activity involves the product of the vivid (vvd) gene (16). Like WC-1, VVD is a PAS/LOV protein and blue-light photoreceptor; however, unlike WC-1, its presence is not essential for circadian rhythmicity in constant darkness (DD) (16)(17)(18)(19). Nevertheless, VVD has important roles within the Neurospora circadian system. Without VVD the organism is more sensitive to ...

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The Coevolution of Blue-Light Photoreception and Circadian Rhythms

Cited by 112 publications

References 35 publications

Phosphorylation of the Cryptochrome 1 C-terminal Tail Regulates Circadian Period Length

Phosphorylation of the Cryptochrome 1 C-terminal Tail Regulates Circadian Period Length

Structure and Function of Animal Cryptochromes

VIVID interacts with the WHITE COLLAR complex and FREQUENCY-interacting RNA helicase to alter light and clock responses in Neurospora

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