The phytochromes: A biochemical mechanism of signaling in sight?

Quail, Peter H.

doi:10.1002/bies.950190708

Cited by 74 publications

(57 citation statements)

References 56 publications

(16 reference statements)

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“…In Arabidopsis thaliana, three major groups of photoreceptors, phytochromes (16), cryptochromes (17), and phototropins (18), have been identified. Phototropins have two LOV (light, oxygen, and voltage) domains, and bind FMN (flavin mononucleotide) as a chromophore (19).…”

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confidence: 99%

Reactive Oxygen Species Affect Photomorphogenesis in Neurospora crassa

Yoshida

Hasunuma

2004

Journal of Biological Chemistry

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In Neurospora crassa, several biological phenomena such as the synthesis of carotenoids in the mycelia and polarity of perithecia are regulated by light. We found that a sod-1 mutant, with a defective Cu,Zn-type superoxide dismutase (SOD), showed accelerated lightdependent induction of carotenoid accumulation in the mycelia compared with the wild type. The initial rate of light-induced carotenoid accumulation in the sod-1 mutant was faster than that in the vvd mutant known to accumulate high concentrations. This acceleration was suppressed by treatment with antioxidant reagents. Light-induced transcription of genes involved in carotenoid synthesis, al-1, -2, and -3, was sustained in the sod-1 mutant, whereas it was transient in the wild type. Moreover sod-1 was defective in terms of light-induced polarity of perithecia. By genetic analysis, the enhancement in light-inducible carotenoid synthesis in sod-1 was dependent on the wild type alleles of wc-1 and wc-2. However, the sod-1;vvd double mutant showed additive effects on the carotenoid accumulation in the mycelia. These results suggested that intracellular reactive oxygen species regulated by SOD-1 could affect the lightsignal transduction pathway via WC proteins.Light is one of the most important environmental factors being utilized for various biological phenomena by living organisms (1, 2). Typical examples are the visual systems in animals, photosynthesis in plants, and photomorphogenesis in fungi. In Neurospora crassa, several biological phenomena are under the control of blue light. Light-induced processes are summarized as follows: (i) synthesis of carotenoids in the mycelia (3), (ii) induction of conidiation (3), (iii) formation of protoperithecia on nitrogen-deficient media (4), (vi) positive phototropism of perithecial beaks (5), (v) positioning of the beak formed on the perithecium (perithecial polarity) (6, 7), and (vi) phase shift in the circadian rhythm of conidiation (8, 9).Much information on photoreceptors and light-inducible genes has been accumulated by genetic and molecular biological analyses to understand the molecular mechanism of these photobiological phenomena. In the search for the blue light photoreceptor in N. crassa, light-insensitive mutants, white collar (wc)1 -1 and wc-2, deficient in most of these blue light responses, have been isolated (4, 10, 11). The products for these genes are photoreceptors that can activate transcription. Both possess a PAS (PER, ARNT, and SIM) domain, a zinc finger DNA binding motif, and a glutamine-rich putative transcription activation domain (12, 13). WC proteins form heterodimers presumably through their PAS domains (14, 15), having promoter binding activity of blue light-regulated genes in Neurospora crassa.In Arabidopsis thaliana, three major groups of photoreceptors, phytochromes (16), cryptochromes (17), and phototropins (18), have been identified. Phototropins have two LOV (light, oxygen, and voltage) domains, and bind FMN (flavin mononucleotide) as a chromophore (19). WC-1 also has one LOV do...

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Reactive Oxygen Species Affect Photomorphogenesis in Neurospora crassa

Yoshida

Hasunuma

2004

Journal of Biological Chemistry

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“…Recently, the nature of the photoreceptors in fungi and plants has been investigated. In Arabidopsis thaliana, the photoreceptors (4,5) are phytochromes (6), cryptochromes (7,8), phototropin (7,9), and zeaxanthin (7). However, the light signal transduction downstream of these photoreceptors has remained to be elucidated unambiguously (10).…”

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A Point Mutation in Nucleoside Diphosphate Kinase Results in a Deficient Light Response for Perithecial Polarity in Neurospora crassa

Ogura

Yoshida

Yabe

et al. 2001

Journal of Biological Chemistry

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In Neurospora crassa, the phosphorylation of nucleoside diphosphate kinase (NDK)-1 is rapidly enhanced after blue light irradiation. We have investigated the function of NDK-1 in the blue light signal transduction pathway. A mutant called psp (phosphorylation of small protein) shows undetectable phosphorylation of NDK-1 and is defective in light-responsive regulation of perithecial polarity. Sequencing analysis of ndk-1 cDNA by reverse transcription-polymerase chain reaction revealed that proline 72 of ndk-1 was replaced with histidine in psp. The mutation ndk-1 P72H resulted in accumulation of normal levels of mRNA and of about 25% of NDK-1 P72H protein compared with that of wild type as determined by Western blot analysis. The ectopic expression of cDNA and introduction of genomic DNA of wild type ndk-1 in psp (ndk-1 P72H ) suppressed the reduction in accumulation and phosphorylation of NDK-1 and the light-insensitive phenotype. These findings demonstrated that the phenotype of psp was caused by the ndk-1 P72H mutation. Biochemical analysis using recombinant NDK-1 and NDK-1 P72H indicated that the P72H substitution in NDK-1 was responsible for the decrease in phosphotransfer activities, 5% of autophosphorylation activity, and 2% of V max for protein kinase activity phosphorylating myelin basic protein, compared with those of wild type NDK-1, respectively.

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“…The first evidence for the kinase activity of phytochrome came essentially from the observation that the purified preparations of phyA autophosphorylate (Wong et al, 1989) and that plant phytochrome and prokaryotic protein kinase sequences resembled significantly (McMichael and Lagarias, 1990). However, the key conserved residues present within a typical histidine kinase domain (HKD) were absent in phytochrome HKRD and thus these observations demonstrating the kinase activity of phytochrome were considered equivocal (Boylan and Quail, 1996;Elich and Chory, 1997;Quail, 1997b;Cashmore, 1998). However, when autophosphorylation/histidine kinase activity of cyanobacterial phytochrome Cph1 was finally established (Hughes et al, 1997;Yeh et al, 1997), the idea that plant phytochromes do indeed behave as a kinase acquired credibility.…”

Section: Phosphorylation and Kinase Activitymentioning

confidence: 99%