The greening process in cress seedlings. V. Possible interference of chlorophyll precursors, accumulated after thujaplicin treatment, with light-regulated expression of Lhc genes

Oster, Ulrike; Brunner, Harald; Rüdiger, Wolfhart

doi:10.1016/s1011-1344(96)07388-5

Cited by 63 publications

(42 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The plants showed decreased amounts of Lhc transcripts by Northern blot hybridization, and decreased Lhc transcription in nuclear run-on assays (Kittsteiner et al 1991). Treatment of cress seedlings with ␤-thujaplicin also resulted in increased amounts of Mg protoporphyrin methyl ester and decreased transcription of Lhcb1, Lhcb2 and Lhca1 (Oster et al 1996). Barley seedlings treated with amitrole, normally regarded as a carotenoid biosynthesis inhibitor, contained increased amounts of Mg protoporphyrin in the dark, and showed decreased expression of Lhcb1 and RbcS when transferred to light (La Rocca et al 2001).…”

Section: Signalling Intermediatesmentioning

confidence: 95%

Coordination of plastid and nuclear gene expression

Gray

Sullivan

Wang

et al. 2003

Phil. Trans. R. Soc. Lond. B

180

178

View full text Add to dashboard Cite

The coordinated expression of genes distributed between the nuclear and plastid genomes is essential for the assembly of functional chloroplasts. Although the nucleus has a pre-eminent role in controlling chloroplast biogenesis, there is considerable evidence that the expression of nuclear genes encoding photosynthesis-related proteins is regulated by signals from plastids. Perturbation of several plastid-located processes, by inhibitors or in mutants, leads to decreased transcription of a set of nuclear photosynthesisrelated genes. Characterization of arabidopsis gun (genomes uncoupled) mutants, which express nuclear genes in the presence of norflurazon or lincomycin, has provided evidence for two separate signalling pathways, one involving tetrapyrrole biosynthesis intermediates and the other requiring plastid protein synthesis. In addition, perturbation of photosynthetic electron transfer produces at least two different redox signals, as part of the acclimation to altered light conditions. The recognition of multiple plastid signals requires a reconsideration of the mechanisms of regulation of transcription of nuclear genes encoding photosynthesis-related proteins.

show abstract

Section: Signalling Intermediatesmentioning

confidence: 95%

Coordination of plastid and nuclear gene expression

Gray

Sullivan

Wang

et al. 2003

Phil. Trans. R. Soc. Lond. B

180

178

View full text Add to dashboard Cite

show abstract

“…These findings implicated Mg-chelatase, Mg-PPIX biosynthesis, or chloroplastic tetrapyrrole metabolism in the plastid-to-nucleus signaling that regulates photosynthesis-related gene expression (Mochizuki et al, 2001). Data generated using distinct experimental approaches provide evidence that Mg-chelatase, Mg-PPIX biosynthesis, or chloroplastic tetrapyrrole metabolism can affect gene expression in Arabidopsis and other plants (Oster et al, 1996;Papenbrock et al, 2000b;Vinti et al, 2000;La Rocca et al, 2001McCormac and Terry, 2002;Strand et al, 2003;Alawady and Grimm, 2005;Gadjieva et al, 2005;Ankele et al, 2007;Zhang et al, 2011), Chlamydomonas reinhardtii (Johanningmeier and Howell, 1984;Kropat et al, 1997Kropat et al, , 2000Falciatore et al, 2005;Vasileuskaya et al, 2005;von Gromoff et al, 2008), and Synechocystis (Osanai et al, 2009). Mg-PPIX also regulates DNA replication in Cyanidioschyzon merolae and tobacco (Nicotiana tabacum) BY-2 cell cultures (Kobayashi et al, 2009).…”

Section: Mutant Alleles Of Gun4 and Mg-chelatase Subunit Genes Do Notmentioning

confidence: 98%

GUN4-Porphyrin Complexes Bind the ChlH/GUN5 Subunit of Mg-Chelatase and Promote Chlorophyll Biosynthesis inArabidopsis

et al. 2011

View full text Add to dashboard Cite

The GENOMES UNCOUPLED4 (GUN4) protein stimulates chlorophyll biosynthesis by activating Mg-chelatase, the enzyme that commits protoporphyrin IX to chlorophyll biosynthesis. This stimulation depends on GUN4 binding the ChlH subunit of Mg-chelatase and the porphyrin substrate and product of Mg-chelatase. After binding porphyrins, GUN4 associates more stably with chloroplast membranes and was proposed to promote interactions between ChlH and chloroplast membranesthe site of Mg-chelatase activity. GUN4 was also proposed to attenuate the production of reactive oxygen species (ROS) by binding and shielding light-exposed porphyrins from collisions with O 2 . To test these proposals, we first engineered Arabidopsis thaliana plants that express only porphyrin binding-deficient forms of GUN4. Using these transgenic plants and particular mutants, we found that the porphyrin binding activity of GUN4 and Mg-chelatase contribute to the accumulation of chlorophyll, GUN4, and Mg-chelatase subunits. Also, we found that the porphyrin binding activity of GUN4 and Mgchelatase affect the associations of GUN4 and ChlH with chloroplast membranes and have various effects on the expression of ROS-inducible genes. Based on our findings, we conclude that ChlH and GUN4 use distinct mechanisms to associate with chloroplast membranes and that mutant alleles of GUN4 and Mg-chelatase genes cause sensitivity to intense light by a mechanism that is potentially complex.

show abstract

“…Feeding and inhibitor experiments have implicated intermediates in the chlorophyll biosynthetic pathway, especially Proto(ME), in plastid-mediated repression of Lhcb genes in Chlamydomonas and cress seedlings (9,41,42), and Proto(ME) feeding activates nuclear heat-shock genes through a light-responsive promoter element in dark-grown Chlamydomonas cultures (10,49). MgProto(ME) levels should be reduced in gun2-gun5 and cch, which is consistent with MgProto(ME) acting as a plastid signal in Arabidopsis.…”

Section: The Chlh Subunit In Chlorophyll Biosynthesis and Plastid Sigmentioning

confidence: 99%

Arabidopsis genomes uncoupled 5 ( GUN5 ) mutant reveals the involvement of Mg-chelatase H subunit in plastid-to-nucleus signal transduction

Mochizuki

Brusslan

Larkin

et al. 2001

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

607

681

View full text Add to dashboard Cite

A plastid-derived signal plays an important role in the coordinated expression of both nuclear-and chloroplast-localized genes that encode photosynthesis-related proteins. Arabidopsis GUN (genomes uncoupled) loci have been identified as components of plastid-to-nucleus signal transduction. Unlike wild-type plants, gun mutants have nuclear Lhcb1 expression in the absence of chloroplast development. We observed a synergistic phenotype in some gun double-mutant combinations, suggesting there are at least two independent pathways in plastid-to-nucleus signal transduction. There is a reduction of chlorophyll accumulation in gun4 and gun5 mutant plants, and a gun4gun5 double mutant shows an albino phenotype. We cloned the GUN5 gene, which encodes the ChlH subunit of Mg-chelatase. We also show that gun2 and gun3 are alleles of the known photomorphogenic mutants, hy1 and hy2, which are required for phytochromobilin synthesis from heme. These findings suggest that certain perturbations of the tetrapyrrole biosynthetic pathway generate a signal from chloroplasts that causes transcriptional repression of nuclear genes encoding plastid-localized proteins. The comparison of mutant phenotypes of gun5 and another Mg-chelatase subunit (ChlI) mutant suggests a specific function for ChlH protein in the plastid-signaling pathway.A number of components required for plastid structure and development are encoded by the nuclear genome. There is a considerable body of evidence that suggests that the proper and timely expression of these genes depends in part on the functional state of the chloroplast. For example, nuclear mutations that result in developmentally arrested chloroplasts also result in the reduced expression of nuclear-localized photosynthetic genes (1). These results tie the functional state of the chloroplast to nuclear function and suggest that the chloroplast signals the nucleus in a retrograde fashion (2).Such retrograde signaling between chloroplast and nucleus has been studied primarily by using carotenoid-deficient plants induced either by mutations or by carotenoid biosynthesis inhibitors such as Norflurazon (Nf; refs. 3 and 4). Carotenoids prevent the production of reactive oxygen species by excited triplet states of chlorophyll. Carotenoid-deficient plants thus suffer a rapid photooxidation of most chloroplast components under intense light. Although most nuclear-encoded cytoplasmic enzymes are present at normal levels in photooxidatively damaged plants, a small set of nuclear-encoded chloroplast enzymes is absent (3, 4). Accordingly, it was hypothesized that plastids send an unknown signal(s) to the nucleus that regulates the expression of a small subset of nuclear-localized photosynthetic genes (2, 5).The molecular nature of the plastid signal(s) and the mechanism by which it is relayed to the nucleus remain ambiguous. Although both plastid transcription and translation are necessary for the production of the plastid signal (4, 6), the plastid signal is not a direct translational product of a plastid gene. Lig...

show abstract

The greening process in cress seedlings. V. Possible interference of chlorophyll precursors, accumulated after thujaplicin treatment, with light-regulated expression of Lhc genes

Cited by 63 publications

References 27 publications

Coordination of plastid and nuclear gene expression

Coordination of plastid and nuclear gene expression

GUN4-Porphyrin Complexes Bind the ChlH/GUN5 Subunit of Mg-Chelatase and Promote Chlorophyll Biosynthesis inArabidopsis

Arabidopsis genomes uncoupled 5 ( GUN5 ) mutant reveals the involvement of Mg-chelatase H subunit in plastid-to-nucleus signal transduction

Contact Info

Product

Resources

About