scholarly journals Retrograde signalling in a virescent mutant triggers an anterograde delay of chloroplast biogenesis that requires GUN1 and is essential for survival

2020 ◽  
Vol 375 (1801) ◽  
pp. 20190400 ◽  
Author(s):  
Naresh Loudya ◽  
Tolulope Okunola ◽  
Jia He ◽  
Paul Jarvis ◽  
Enrique López-Juez
Keyword(s):  
Protein Import ◽  
Early Stage ◽  
Plastid Development ◽  
Plastid Genomes ◽  
Expression Of Genes ◽  
Fitness Value ◽  
Retrograde Signalling ◽  
Value Loss ◽  
Elevated Expression ◽  
Plastid Protein

Defects in chloroplast development are ‘retrograde-signalled’ to the nucleus, reducing synthesis of photosynthetic or related proteins. The Arabidopsis cue8 mutant manifests virescence, a slow-greening phenotype, and is defective at an early stage in plastid development. Greening cotyledons or early leaf cells of cue8 exhibit immature chloroplasts which fail to fill the available cellular space. Such chloroplasts show reduced expression of genes of photosynthetic function, dependent on the plastid-encoded polymerase (PEP), while the expression of genes of housekeeping function driven by the nucleus-encoded polymerase (NEP) is elevated, a phenotype shared with mutants in plastid genetic functions. We attribute this phenotype to reduced expression of specific PEP-controlling sigma factors, elevated expression of RPOT (NEP) genes and maintained replication of plastid genomes (resulting in densely coalesced nucleoids in the mutant), i.e. it is due to an anterograde nucleus-to-chloroplast correction, analogous to retention of a juvenile plastid state. Mutants in plastid protein import components, particularly those involved in housekeeping protein import, also show this ‘retro-anterograde’ correction. Loss of CUE8 also causes changes in mRNA editing. The overall response has strong fitness value: loss of GUN1, an integrator of retrograde signalling, abolishes elements of it (albeit not others, including editing changes), causing bleaching and eventual seedling lethality upon cue8 gun1 . This highlights the adaptive significance of virescence and retrograde signalling. This article is part of the theme issue ‘Retrograde signalling from endosymbiotic organelles’.

scholarly journals Coordination of plastid and nuclear gene expression

2003 ◽  
Vol 358 (1429) ◽  
pp. 135-145 ◽  
Author(s):  
John C. Gray ◽  
James A. Sullivan ◽  
Jun-Hui Wang ◽  
Cheryl A. Jerome ◽  
Daniel MacLean
Keyword(s):  
Nuclear Gene ◽  
Nuclear Genes ◽  
Regulation Of Transcription ◽  
Nuclear Gene Expression ◽  
Plastid Genomes ◽  
Expression Of Genes ◽  
Genes Encoding ◽  
Coordinated Expression ◽  
Plastid Protein ◽  
Related Proteins

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 photosynthesis–related 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.

scholarly journals The Role of Tetrapyrrole- and GUN1-Dependent Signaling on Chloroplast Biogenesis

Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 196
Author(s):  
Takayuki Shimizu ◽  
Tatsuru Masuda
Keyword(s):  
Protein Import ◽  
Nuclear Gene ◽  
Retrograde Signaling ◽  
Chloroplast Biogenesis ◽  
Plastid Development ◽  
Nuclear Gene Expression ◽  
Coordinated Expression ◽  
Plastid Protein ◽  
Working Hypotheses

Chloroplast biogenesis requires the coordinated expression of the chloroplast and nuclear genomes, which is achieved by communication between the developing chloroplasts and the nucleus. Signals emitted from the plastids, so-called retrograde signals, control nuclear gene expression depending on plastid development and functionality. Genetic analysis of this pathway identified a set of mutants defective in retrograde signaling and designated genomes uncoupled (gun) mutants. Subsequent research has pointed to a significant role of tetrapyrrole biosynthesis in retrograde signaling. Meanwhile, the molecular functions of GUN1, the proposed integrator of multiple retrograde signals, have not been identified yet. However, based on the interactions of GUN1, some working hypotheses have been proposed. Interestingly, GUN1 contributes to important biological processes, including plastid protein homeostasis, through transcription, translation, and protein import. Furthermore, the interactions of GUN1 with tetrapyrroles and their biosynthetic enzymes have been revealed. This review focuses on our current understanding of the function of tetrapyrrole retrograde signaling on chloroplast biogenesis.

Differential accumulation of plastid preprotein translocon components during spruce (Picea abies L. Karst.) needle development

2005 ◽  
Vol 386 (8) ◽  
pp. 777-783 ◽  
Author(s):  
Hrvoje Fulgosi ◽  
Hrvoje Lepeduš ◽  
Vera Cesar ◽  
Nikola Ljubešić
Keyword(s):  
Protein Import ◽  
Protein Translocation ◽  
Early Stage ◽  
Small Subunit ◽  
Outer Envelope ◽  
Receptor Isoforms ◽  
Evolutionarily Conserved ◽  
Functional Complex ◽  
Plastid Protein ◽  
Preprotein Translocation

Abstract We demonstrate that basic components of the plastid protein-import apparatus originally found in pea, Toc34, Toc159, and Tic110, are also conserved in evolutionarily younger gymnosperms. We show that multiple isoforms of the preprotein receptor Toc34 differentially accumulate in various stages of needle development, while the amounts of Toc159 drastically decrease during chloroplast morphogenesis. Spruce Toc34 and Toc159 receptors are able to recognise and interact with the angiosperm precursor of the Rubisco small subunit. Young proplastids found in closed buds contain a highly elevated number of protein translocation complexes equipped with only two types of outer envelope receptors, Toc159 and a 30-kDa Toc34-related protein. Photosystem II (PSII) can already be assembled in a fully functional complex at this very early stage of needle development, suggesting that no additional receptor isoforms are needed for translocation of all necessary PSII components. We conclude that the accumulation of evolutionarily conserved plastid preprotein translocation components is differentially regulated during spruce needle development.

scholarly journals Changes in Photosynthesis Could Provide Important Insight into the Interaction between Wheat and Fungal Pathogens

2021 ◽  
Vol 22 (16) ◽  
pp. 8865
Author(s):  
Huai Yang ◽  
Peigao Luo
Keyword(s):  
Fungal Pathogens ◽  
Puccinia Striiformis ◽  
Early Stage ◽  
Acquired Resistance ◽  
Immune Defense ◽  
Pathogen Infection ◽  
Resistance Level ◽  
Growth Environment ◽  
Expression Of Genes ◽  
Host Materials

Photosynthesis is a universal process for plant survival, and immune defense is also a key process in adapting to the growth environment. Various studies have indicated that these two processes are interconnected in a complex network. Photosynthesis can influence signaling pathways and provide both materials and energy for immune defense, while the immune defense process can also have feedback effects on photosynthesis. Pathogen infection inevitably leads to changes in photosynthesis parameters, including Pn, Gs, and Ci; biochemical materials such as SOD and CAT; signaling molecules such as H2O2 and hormones; and the expression of genes involved in photosynthesis. Some researchers have found that changes in photosynthesis activity are related to the resistance level of the host, the duration after infection, and the infection position (photosynthetic source or sink). Interactions between wheat and the main fungal pathogens, such as Puccinia striiformis, Blumeria graminis, and Fusarium graminearum, constitute an ideal study system to elucidate the relationship between changes in host photosynthesis and resistance levels, based on the accessibility of methods for artificially controlling infection and detecting changes in photosynthesis, the presence of multiple pathogens infecting different positions, and the abundance of host materials with various resistance levels. This review is written only from the perspective of plant pathologists, and after providing an overview of the available data, we generally found that changes in photosynthesis in the early stage of pathogen infection could be a causal factor influencing acquired resistance, while those in the late stage could be the result of resistance formation.

scholarly journals Mitochondrial OXPHOS Biogenesis: Co-Regulation of Protein Synthesis, Import, and Assembly Pathways

2020 ◽  
Vol 21 (11) ◽  
pp. 3820 ◽  
Author(s):  
Jia Xin Tang ◽  
Kyle Thompson ◽  
Robert W. Taylor ◽  
Monika Oláhová
Keyword(s):  
Gene Expression ◽  
Protein Synthesis ◽  
Protein Import ◽  
Acyl Carrier Protein ◽  
Early Stage ◽  
Mitochondrial Gene ◽  
Mitochondrial Protein ◽  
Fine Tuning ◽  
Mitochondrial Translation ◽  
Oxphos Complex

The assembly of mitochondrial oxidative phosphorylation (OXPHOS) complexes is an intricate process, which—given their dual-genetic control—requires tight co-regulation of two evolutionarily distinct gene expression machineries. Moreover, fine-tuning protein synthesis to the nascent assembly of OXPHOS complexes requires regulatory mechanisms such as translational plasticity and translational activators that can coordinate mitochondrial translation with the import of nuclear-encoded mitochondrial proteins. The intricacy of OXPHOS complex biogenesis is further evidenced by the requirement of many tightly orchestrated steps and ancillary factors. Early-stage ancillary chaperones have essential roles in coordinating OXPHOS assembly, whilst late-stage assembly factors—also known as the LYRM (leucine–tyrosine–arginine motif) proteins—together with the mitochondrial acyl carrier protein (ACP)—regulate the incorporation and activation of late-incorporating OXPHOS subunits and/or co-factors. In this review, we describe recent discoveries providing insights into the mechanisms required for optimal OXPHOS biogenesis, including the coordination of mitochondrial gene expression with the availability of nuclear-encoded factors entering via mitochondrial protein import systems.

Investigation of GSTP1 and epigenetic regulators expression pattern in a population of Iranian patients with prostate cancer

2020 ◽  
Vol 28 (4) ◽  
pp. 327-334
Author(s):  
Mahan Mohammadi ◽  
Shiva Irani ◽  
Iman Salahshourifar ◽  
Jalil Hosseini ◽  
Afshin Moradi ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
High Efficiency ◽  
Rna Extraction ◽  
P Value ◽  
Prostate Hyperplasia ◽  
Expression Of Genes ◽  
Elevated Expression ◽  
Epigenetic Regulators ◽  
The Impact ◽  
Iranian Patients

BACKGROUND AND AIM: Prostate cancer is the leading cause of death in many countries. It is important to diagnose the disease in the early stages. Current methods detect the disease with low specificity. Examining the expression of genes responsible for disease and their epigenetic regulators are good tools in this regard. MATERIAL AND METHODS: In this prospective case-control study, 40 Iranian patients with cancer, 40 Iranian patients with prostate hyperplasia, and 40 control samples were examined. After blood sampling from each individual, RNA extraction and cDNA synthesis, GSTP1, HDAC, DNMT3A, and DNMT3B expressions were measured in three understudy groups using specific primers and Real-Time PCR method. RESULTS: A reverse correlation was identified between loss of GSTP1 expression and overexpression of HDAC, DNMT3A, and DNMT3B (P value < 0.0001) with a beneficial pattern of cancer development with high efficiency. The significant decrease of GSTP1 expression in patients in comparison to the healthy controls and the elevated expression levels of the studied epigenetic regulators in PCA and BPH samples indicate the impact of the regulators on GSTP1 expression activity. CONCLUSION: This study showed that the measurement of combined GSTP1 and its epigenetic regulators’ expression could be used as suitable genetic markers for the detection and separation of healthy individuals from prostatic patient groups in the Iranian population. However, a similar study in a larger population of case and control could help us to distinguish between normal, benign, and malignant conditions.

scholarly journals The essential yeast protein MIM44 (encoded by MPI1) is involved in an early step of preprotein translocation across the mitochondrial inner membrane.

1993 ◽  
Vol 13 (12) ◽  
pp. 7364-7371 ◽  
Author(s):  
J Blom ◽  
M Kübrich ◽  
J Rassow ◽  
W Voos ◽  
P J Dekker ◽  
...  
Keyword(s):  
Protein Import ◽  
Early Stage ◽  
Proteolytic Processing ◽  
Early Step ◽  
Direct Role ◽  
Inner Membrane ◽  
Mitochondrial Inner Membrane ◽  
Preprotein Translocation ◽  
In Transit

The essential yeast gene MPI1 encodes a mitochondrial membrane protein that is possibly involved in protein import into the organelle (A. C. Maarse, J. Blom, L. A. Grivell, and M. Meijer, EMBO J. 11:3619-3628, 1992). For this report, we determined the submitochondrial location of the MPI1 gene product and investigated whether it plays a direct role in the translocation of preproteins. By fractionation of mitochondria, the mature protein of 44 kDa was localized to the mitochondrial inner membrane and therefore termed MIM44. Import of the precursor of MIM44 required a membrane potential across the inner membrane and involved proteolytic processing of the precursor. A preprotein in transit across the mitochondrial membranes was cross-linked to MIM44, whereas preproteins arrested on the mitochondrial surface or fully imported proteins were not cross-linked. When preproteins were arrested at two distinct stages of translocation across the inner membrane, only preproteins at an early stage of translocation could be cross-linked to MIM44. Moreover, solubilized MIM44 was found to interact with in vitro-synthesized preproteins. We conclude that MIM44 is a component of the mitochondrial inner membrane import machinery and interacts with preproteins in an early step of translocation.

scholarly journals Role of the cytoskeleton in muscle transcriptional responses to altered use

2013 ◽  
Vol 45 (8) ◽  
pp. 321-331 ◽  
Author(s):  
Gretchen A. Meyer ◽  
Simon Schenk ◽  
Richard L. Lieber
Keyword(s):  
Mechanical Response ◽  
Fiber Type ◽  
Transcriptional Response ◽  
Primary Component ◽  
Transcriptional Responses ◽  
Expression Of Genes ◽  
Elevated Expression ◽  
Transcriptional Changes ◽  
Type Shift ◽  
Future Work

In this work, the interaction between the loss of a primary component of the skeletal muscle cytoskeleton, desmin, and two common physiological stressors, acute mechanical injury and aging, were investigated at the transcriptional, protein, and whole muscle levels. The transcriptional response of desmin knockout ( des −/−) plantarflexors to a bout of 50 eccentric contractions (ECCs) showed substantial overlap with the response in wild-type ( wt) muscle. However, changes in the expression of genes involved in muscle response to injury were blunted in adult des −/− muscle compared with wt (fold change with ECC in des −/− and wt, respectively: Mybph, 1.4 and 2.9; Xirp1, 2.2 and 5.7; Csrp3, 1.8 and 4.3), similar to the observed blunted mechanical response (torque drop: des −/− 30.3% and wt 55.5%). Interestingly, in the absence of stressors, des −/− muscle exhibited elevated expression of many these genes compared with wt. The largest transcriptional changes were observed in the interaction between aging and the absence of desmin, including many genes related to slow fiber pathway (Myh7, Myl3, Atp2a2, and Casq2) and insulin sensitivity (Tlr4, Trib3, Pdk3, and Pdk4). Consistent with these transcriptional changes, adult des −/− muscle exhibited a significant fiber type shift from fast to slow isoforms of myosin heavy chain ( wt, 5.3% IIa and 71.7% IIb; des −/−, 8.4% IIa and 61.4% IIb) and a decreased insulin-stimulated glucose uptake ( wt, 0.188 μmol/g muscle/20 min; des −/−, 0.085 μmol/g muscle/20 min). This work points to novel areas of influence of this cytoskeletal protein and directs future work to elucidate its function.

Sign in / Sign up

Export Citation Format

Share Document