Chloroplast-mediated regulation of nuclear genes in Arabidopsis thaliana in the absence of light stress

2006 ◽  
Vol 25 (1) ◽  
pp. 142-152 ◽  
Author(s):  
Mirva Piippo ◽  
Yagut Allahverdiyeva ◽  
Virpi Paakkarinen ◽  
Ulla-Maija Suoranta ◽  
Natalia Battchikova ◽  
...  
Keyword(s):  
Gene Expression ◽  
Photosystem I ◽  
Redox State ◽  
Light Stress ◽  
Calvin Cycle ◽  
Nuclear Gene ◽  
Fixation Rate ◽  
Plastoquinone Pool ◽  
Nuclear Gene Expression ◽  
Genes Encoding

Chloroplast signaling involves mechanisms to relay information from chloroplasts to the nucleus, to change nuclear gene expression in response to environmental cues. Aside from reactive oxygen species (ROS) produced under stress conditions, changes in the reduction/oxidation state of photosynthetic electron transfer components or coupled compounds in the stroma and the accumulation of photosynthesis-derived metabolites are likely origins of chloroplast signals. We attempted to investigate the origin of the signals from chloroplasts in mature Arabidopsis leaves by differentially modulating the redox states of the plastoquinone pool and components on the reducing side of photosystem I, as well as the rate of CO2 fixation, while avoiding the production of ROS by excess light. Differential expression of several nuclear photosynthesis genes, including a set of Calvin cycle enzymes, was recorded. These responded to the stromal redox conditions under prevailing light conditions but were independent of the redox state of the plastoquinone pool. The steady-state CO2 fixation rate was reflected in the orchestration of the expression of a number of genes encoding cytoplasmic proteins, including several glycolysis genes and the trehalose-6-phosphate synthase gene, and also the chloroplast-targeted chaperone DnaJ. Clearly, in mature leaves, the redox state of the compounds on the reducing side of photosystem I is of greater importance in light-dependent modulation of nuclear gene expression than the redox state of the plastoquinone pool, particularly at early signaling phases. It also became apparent that photosynthesis-mediated generation of metabolites or signaling molecules is involved in the relay of information from chloroplast to nucleus.

scholarly journals Overexpression of chloroplast-targeted ferrochelatase 1 results in a genomes uncoupled chloroplast-to-nucleus retrograde signalling phenotype

2020 ◽  
Vol 375 (1801) ◽  
pp. 20190401 ◽  
Author(s):  
Mike T. Page ◽  
Tania Garcia-Becerra ◽  
Alison G. Smith ◽  
Matthew J. Terry
Keyword(s):  
Gene Expression ◽  
Feedback Inhibition ◽  
Nuclear Gene ◽  
Signalling Pathway ◽  
Chloroplast Genes ◽  
Nuclear Gene Expression ◽  
Retrograde Signalling ◽  
Genes Encoding ◽  
Retrograde Signal

Chloroplast development requires communication between the progenitor plastids and the nucleus, where most of the genes encoding chloroplast proteins reside. Retrograde signals from the chloroplast to the nucleus control the expression of many of these genes, but the signalling pathway is poorly understood. Tetrapyrroles have been strongly implicated as mediators of this signal with the current hypothesis being that haem produced by the activity of ferrochelatase 1 (FC1) is required to promote nuclear gene expression. We have tested this hypothesis by overexpressing FC1 and specifically targeting it to either chloroplasts or mitochondria, two possible locations for this enzyme. Our results show that targeting of FC1 to chloroplasts results in increased expression of the nuclear-encoded chloroplast genes GUN4 , CA1 , HEMA1 , LHCB2.1, CHLH after treatment with Norflurazon (NF) and that this increase correlates to FC1 gene expression and haem production measured by feedback inhibition of protochlorophyllide synthesis. Targeting FC1 to mitochondria did not enhance the expression of nuclear-encoded chloroplast genes after NF treatment. The overexpression of FC1 also increased nuclear gene expression in the absence of NF treatment, demonstrating that this pathway is operational in the absence of a stress treatment. Our results therefore support the hypothesis that haem synthesis is a promotive chloroplast-to-nucleus retrograde signal. However, not all FC1 overexpression lines enhanced nuclear gene expression, suggesting there is still a lot we do not understand about the role of FC1 in this signalling pathway. This article is part of the theme issue ‘Retrograde signalling from endosymbiotic organelles’.

The oxen Gene of Drosophila Encodes a Homolog of Subunit 9 of Yeast Ubiquinol-Cytochrome c Oxidoreductase Complex: Evidence for Modulation of Gene Expression in Response to Mitochondrial Activity

Genetics ◽  
2000 ◽  
Vol 156 (4) ◽  
pp. 1727-1736 ◽  
Author(s):  
Maxim V Frolov ◽  
Elizaveta V Benevolenskaya ◽  
James A Birchler
Keyword(s):  
Gene Expression ◽  
Cytochrome C ◽  
Cellular Response ◽  
Insertion Site ◽  
Nuclear Gene ◽  
Mutant Phenotype ◽  
P Element ◽  
Mitochondrial Activity ◽  
Genes Encoding ◽  
Subunit 9

Abstract A P-element insertion in the oxen gene, ox1, has been isolated in a search for modifiers of white gene expression. The mutation preferentially exerts a negative dosage effect upon the expression of three genes encoding ABC transporters involved in pigment precursor transport, white, brown, and scarlet. A precise excision of the P element reverts the mutant phenotype. Five different transcription units were identified around the insertion site. To distinguish a transcript responsible for the mutant phenotype, a set of deletions within the oxen region was generated. Analysis of gene expression within the oxen region in the case of deletions as well as generation of transgenic flies allowed us to identify the transcript responsible for oxen function. It encodes a 6.6-kD homolog of mitochondrial ubiquinol cytochrome c oxidoreductase (QCR9), subunit 9 of the bc1 complex in yeast. In addition to white, brown, and scarlet, oxen regulates the expression of three of seven tested genes. Thus, our data provide additional evidence for a cellular response to changes in mitochondrial function. The oxen mutation provides a model for the genetic analysis in multicellular organisms of the effect of mitochondrial activity on nuclear gene expression.

Chloroplast Redox Control of Nuclear Gene Expression—A New Class of Plastid Signals in Interorganellar Communication

2003 ◽  
Vol 5 (1) ◽  
pp. 95-101 ◽  
Author(s):  
Thomas Pfannschmidt ◽  
Katia Schütze ◽  
Vidal Fey ◽  
Irena Sherameti ◽  
Ralf Oelmüller
Keyword(s):  
Gene Expression ◽  
Nuclear Gene ◽  
Redox Control ◽  
New Class ◽  
Nuclear Gene Expression

scholarly journals Introns mediate post-transcriptional enhancement of nuclear gene expression in the green microalga Chlamydomonas reinhardtii

PLoS Genetics ◽  
2020 ◽  
Vol 16 (7) ◽  
pp. e1008944 ◽  
Author(s):  
Thomas Baier ◽  
Nick Jacobebbinghaus ◽  
Alexander Einhaus ◽  
Kyle J. Lauersen ◽  
Olaf Kruse
Keyword(s):  
Gene Expression ◽  
Chlamydomonas Reinhardtii ◽  
Nuclear Gene ◽  
Nuclear Gene Expression ◽  
Green Microalga

scholarly journals Dinoflagellate Host Chloroplasts and Mitochondria Remain Functional During Amoebophrya Infection

2020 ◽  
Vol 11 ◽  
Author(s):  
Ehsan Kayal ◽  
Catharina Alves-de-Souza ◽  
Sarah Farhat ◽  
Lourdes Velo-Suarez ◽  
Joanne Monjol ◽  
...  
Keyword(s):  
Gene Expression ◽  
Carbon Fixation ◽  
Nuclear Gene ◽  
Host Cells ◽  
Infection Period ◽  
Nuclear Gene Expression ◽  
Intracellular Parasites ◽  
Electron Transport Chains ◽  
Complete Digestion ◽  
Host Nucleus

Dinoflagellates are major components of phytoplankton that play critical roles in many microbial food webs, many of them being hosts of countless intracellular parasites. The phototrophic dinoflagellate Scrippsiella acuminata (Dinophyceae) can be infected by the microeukaryotic parasitoids Amoebophrya spp. (Syndiniales), some of which primarily target and digest the host nucleus. Early digestion of the nucleus at the beginning of the infection is expected to greatly impact the host metabolism, inducing the knockout of the organellar machineries that highly depend upon nuclear gene expression, such as the mitochondrial OXPHOS pathway and the plastid photosynthetic carbon fixation. However, previous studies have reported that chloroplasts remain functional in swimming host cells infected by Amoebophrya. We report here a multi-approach monitoring study of S. acuminata organelles over a complete infection cycle by nucleus-targeting Amoebophrya sp. strain A120. Our results show sustained and efficient photosystem II activity as a hallmark of functional chloroplast throughout the infection period despite the complete digestion of the host nucleus. We also report the importance played by light on parasite production, i.e., the amount of host biomass converted to parasite infective propagules. Using a differential gene expression analysis, we observed an apparent increase of all 3 mitochondrial and 9 out of the 11 plastidial genes involved in the electron transport chains (ETC) of the respiration pathways during the first stages of the infection. The longer resilience of organellar genes compared to those encoded by the nucleus suggests that both mitochondria and chloroplasts remain functional throughout most of the infection. This extended organelle functionality, along with higher parasite production under light conditions, suggests that host bioenergetic organelles likely benefit the parasite Amoebophrya sp. A120 and improve its fitness during the intracellular infective stage.

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