A Tale of Two Genomes: Role of a Chloroplast Signal in Coordinating Nuclear and Plastid Genome Expression

Susek, R E; Chory, Joanne

doi:10.1071/pp9920387

Cited by 91 publications

(95 citation statements)

References 78 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These data indicate that gun mutant screens specifically disrupted a few distinct mechanisms that downregulate the expression of PhANGs when chloroplast biogenesis is blocked, not complex metabolic situations. The findings that these mechanisms appear conserved in all plants tested [17] and contribute to stress tolerance [4,5,11,14], the circadian rhythm [7,8] and development [38][39][40][41] provide evidence that they contribute plastid-to-nucleus signalling in natural environments.…”

Section: The Gun Mutant Screenmentioning

confidence: 99%

“…The gun alleles that attenuate tetrapyrrole metabolism were suggested to cause resistance to norflurazon [42,43] because norflurazon was thought to promote collisions between ground-state triplet oxygen and triplet chlorophyll, which yield singlet oxygen ( 1 O 2 ), a toxic reactive oxygen species (ROS). This 1 O 2 was thought to block chloroplast biogenesis [16,17]. Recent data provide compelling evidence that norflurazon blocks chloroplast biogenesis not by affecting the levels of 1 O 2 but perhaps by causing the misfolding of the chlorophyll-and carotenoid-binding proteins of the thylakoid membranes [44].…”

Section: The Gun Mutant Screenmentioning

confidence: 99%

“…When chloroplast biogenesis is blocked with mutant alleles or inhibitors, the transcription of most PhANGs is severely downregulated. Thus, dysfunctional chloroplasts were proposed to emit signals that negatively regulate the transcription of PhANGs [16,17]. Attenuating the activity of well-functioning chloroplasts was found to also activate this signalling [18,19].…”

Section: The Gun Mutant Screenmentioning

confidence: 99%

“…gun mutant screens use reporter genes to screen for Arabidopsis mutants that transcribe elevated levels of PhANGs when chloroplast biogenesis is blocked with norflurazon treatments [5,18,[20][21][22]. Norflurazon specifically inhibits phytoene desaturase, which is required for carotenoid biosynthesis and chloroplast biogenesis [17]. gun alleles either attenuate negative regulators or promote positive regulators of PhANG expression [5,18,[20][21][22][23][24][25].…”

Section: The Gun Mutant Screenmentioning

confidence: 99%

“…The gun mutant screen was the first screen for mutant alleles that disrupt plastid-to-nucleus signalling [17,20]. gun mutant screens use reporter genes to screen for Arabidopsis mutants that transcribe elevated levels of PhANGs when chloroplast biogenesis is blocked with norflurazon treatments [5,18,[20][21][22].…”

Section: The Gun Mutant Screenmentioning

confidence: 99%

See 4 more Smart Citations

Influence of plastids on light signalling and development

Larkin

2014

Phil. Trans. R. Soc. B

View full text Add to dashboard Cite

In addition to their contribution to metabolism, chloroplasts emit signals that influence the expression of nuclear genes that contribute to numerous plastidic and extraplastidic processes. Plastid-to-nucleus signalling optimizes chloroplast function, regulates growth and development, and affects responses to environmental cues. An incomplete list of plastid signals is available and particular plastid-to-nucleus signalling mechanisms are partially understood. The plastid-to-nucleus signalling that depends on the GENOMES UNCOUPLED ( GUN ) genes couples the expression of nuclear genes to the functional state of the chloroplast. Analyses of gun mutants provided insight into the mechanisms and biological functions of plastid-to-nucleus signalling. GUN genes contribute to chloroplast biogenesis, the circadian rhythm, stress tolerance, light signalling and development. Some have criticized the gun mutant screen for employing inhibitors of chloroplast biogenesis and suggested that gun alleles do not disrupt significant plastid-to-nucleus signalling mechanisms. Here, I briefly review GUN -dependent plastid-to-nucleus signalling, explain the flaws in the major criticisms of the gun mutant screen and review the influence of plastids on light signalling and development.

show abstract

Section: The Gun Mutant Screenmentioning

confidence: 99%

Section: The Gun Mutant Screenmentioning

confidence: 99%

Section: The Gun Mutant Screenmentioning

confidence: 99%

Section: The Gun Mutant Screenmentioning

confidence: 99%

Section: The Gun Mutant Screenmentioning

confidence: 99%

See 3 more Smart Citations

Influence of plastids on light signalling and development

Larkin

2014

Phil. Trans. R. Soc. B

View full text Add to dashboard Cite

show abstract

Pathways of intracellular communication: Tetrapyrroles and plastid‐to‐nucleus signaling

Rodermel

Park

2003

BioEssays

View full text Add to dashboard Cite

Retrograde plastid-to-nucleus signaling plays a central role in coordinating nuclear and plastid gene expression. The gun (genomes uncoupled) mutants of Arabidopsis have been used to demonstrate that Mg-protoporphyrin (Mg-Proto) acts as a plastid signal to repress the transcription of nuclear photosynthesis genes (1). It is unclear how Mg-Proto triggers repression, but several components of this pathway have been recently identified. These include the products of GUN4 and GUN5. GUN5 is the ChlH subunit of Mg-chelatase, which produces Mg-Proto, and GUN4 is a regulator of ChlH activity (2). GUN4 might also play a role in photoprotection and in the trafficking of Mg-Proto.

show abstract

DAG, a gene required for chloroplast differentiation and palisade development in Antirrhinum majus.

et al. 1996

View full text Add to dashboard Cite

We have identified a mutation at the DAG locus of Antirrhinum majus which blocks the development of chloroplasts to give white leaves with green revertant sectors. The green areas contain normal chloroplasts whereas the white areas have small plastids that resemble proplastids. The cotyledons of dark‐grown dag mutant seedlings have plastids which also resemble proplastids. The palisade cells in the white areas of dag mutant leaves also lack their characteristic columnar shape. The DAG locus was cloned by transposon tagging: DAG encodes a novel protein with a predicted Mr of 26k, which is targeted to the plastids. Cleavage of its predicted transit peptide gives a mature protein of Mr 20k. Screening of databases and analysis of Southern blots gave evidence that DAG belongs to a protein family with homology to several proteins of unknown function from plants. Expression of DAG is required for expression of nuclear genes affecting the chloroplasts, such as CAB and RBCS, and also for expression of the plastidial gene RPOB encoding the plastidial RNA polymerase beta subunit, indicating that it functions very early in chloroplast development.

show abstract

A Tale of Two Genomes: Role of a Chloroplast Signal in Coordinating Nuclear and Plastid Genome Expression

Cited by 91 publications

References 78 publications

Influence of plastids on light signalling and development

Influence of plastids on light signalling and development

Pathways of intracellular communication: Tetrapyrroles and plastid‐to‐nucleus signaling

DAG, a gene required for chloroplast differentiation and palisade development in Antirrhinum majus.

Contact Info

Product

Resources

About