Publications by authors named "Sumire Ono"

5 Publications

  • Page 1 of 1

The evolutionary conserved iron-sulfur protein TCR controls P700 oxidation in photosystem I.

iScience 2021 Feb 13;24(2):102059. Epub 2021 Jan 13.

Department of Life Science and Technology, Tokyo Institute of Technology, Yokohama 226-8501, Japan.

In natural habitats, plants have developed sophisticated regulatory mechanisms to optimize the photosynthetic electron transfer rate at the maximum efficiency and cope with the changing environments. Maintaining proper P700 oxidation at photosystem I (PSI) is the common denominator for most regulatory processes of photosynthetic electron transfers. However, the molecular complexes and cofactors involved in these processes and their function(s) have not been fully clarified. Here, we identified a redox-active chloroplast protein, the triplet-cysteine repeat protein (TCR). TCR shared similar expression profiles with known photosynthetic regulators and contained two triplet-cysteine motifs (CxxxCxxxC). Biochemical analysis indicated that TCR localizes in chloroplasts and has a [3Fe-4S] cluster. Loss of TCR limited the electron sink downstream of PSI during dark-to-light transition. double mutant reduced growth significantly and showed unusual oxidation and reduction of plastoquinone pool. These results indicated that TCR is involved in electron flow(s) downstream of PSI, contributing to P700 oxidation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.isci.2021.102059DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7848650PMC
February 2021

Plastidial (p)ppGpp Synthesis by the Ca2+-Dependent RelA-SpoT Homolog Regulates the Adaptation of Chloroplast Gene Expression to Darkness in Arabidopsis.

Plant Cell Physiol 2021 Feb;61(12):2077-2086

Graduate School of Life Science & Technology, Tokyo Institute of Technology, Yokohama, 226-8501 Japan.

In bacteria, the hyper-phosphorylated nucleotide, guanosine 3',5'-bis(pyrophosphate) (ppGpp), functions as a secondary messenger under stringent conditions. ppGpp levels are controlled by two distinct enzymes, namely RelA and SpoT, in Escherichia coli. RelA-SpoT homologs (RSHs) are also conserved in plants where they function in the plastids. The model plant Arabidopsis thaliana contains four RSHs: RSH1, RSH2, RSH3 and Ca2+-dependent RSH (CRSH). Genetic characterizations of RSH1, RSH2 and RSH3 were undertaken, which showed that the ppGpp-dependent plastidial stringent response significantly influences plant growth and stress acclimation. However, the physiological significance of CRSH-dependent ppGpp synthesis remains unclear, as no crsh-null mutant has been available. Here, to investigate the function of CRSH, a crsh-knockout mutant of Arabidopsis was constructed using a site-specific gene-editing technique, and its phenotype was characterized. A transient increase in ppGpp was observed for 30 min in the wild type (WT) after the light-to-dark transition, but this increase was not observed in the crsh mutant. Similar analyses were performed with the rsh2-rsh3 double and rsh1-rsh2-rsh3 triple mutants and showed that the transient increments of ppGpp in the mutants were higher than those in the WT. The increase in ppGpp in the WT and rsh2 rsh3 accompanied decrements in the mRNA levels of some plastidial genes transcribed by the plastid-encoded plastid RNA polymerase. These results indicate that the transient increase in ppGpp at night is due to CRSH-dependent ppGpp synthesis and that the ppGpp level is maintained by the hydrolytic activities of RSH1, RSH2 and RSH3 to accustom plastidial gene expression to darkness.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/pcp/pcaa124DOI Listing
February 2021

Blockade of T-type calcium channels by 6-prenylnaringenin, a hop component, alleviates neuropathic and visceral pain in mice.

Neuropharmacology 2018 08 18;138:232-244. Epub 2018 Jun 18.

Laboratory of Pharmacology and Pathophysiology, Faculty of Pharmacy, Kindai University, Higashi-Osaka, 577-8502, Japan. Electronic address:

Since Ca3.2 T-type Ca channels (T-channels) expressed in the primary afferents and CNS contribute to intractable pain, we explored T-channel-blocking components in distinct herbal extracts using a whole-cell patch-clamp technique in HEK293 cells stably expressing Ca3.2 or Ca3.1, and purified and identified sophoraflavanone G (SG) as an active compound from SOPHORAE RADIX (SR). Interestingly, hop-derived SG analogues, (2S)-6-prenylnaringenin (6-PNG) and (2S)-8-PNG, but not naringenin, also blocked T-channels; IC (μM) of SG, (2S)-6-PNG and (2S)-8-PNG was 0.68-0.75 for Ca3.2 and 0.99-1.41 for Ca3.1. (2S)-6-PNG and (2S)-8-PNG, but not SG, exhibited reversible inhibition. The racemic (2R/S)-6-PNG as well as (2S)-6-PNG potently blocked Ca3.2, but exhibited minor effect on high-voltage-activated Ca channels and voltage-gated Na channels in differentiated NG108-15 cells. In mice, the mechanical allodynia following intraplantar (i.pl.) administration of an HS donor was abolished by oral or i.p. SR extract and by i.pl. SG, (2S)-6-PNG or (2S)-8-PNG, but not naringenin. Intraperitoneal (2R/S)-6-PNG strongly suppressed visceral pain and spinal ERK phosphorylation following intracolonic administration of an HS donor in mice. (2R/S)-6-PNG, administered i.pl. or i.p., suppressed the neuropathic allodynia induced by partial sciatic nerve ligation or oxaliplatin, an anti-cancer agent, in mice. (2R/S)-6-PNG had little or no effect on open-field behavior, motor performance or cardiovascular function in mice, and on the contractility of isolated rat aorta. (2R/S)-6-PNG, but not SG, was detectable in the brain after their i.p. administration in mice. Our data suggest that 6-PNG, a hop component, blocks T-channels, and alleviates neuropathic and visceral pain with little side effects.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.neuropharm.2018.06.020DOI Listing
August 2018

Significance of accumulation of the alarmone (p)ppGpp in chloroplasts for controlling photosynthesis and metabolite balance during nitrogen starvation in Arabidopsis.

Photosynth Res 2018 Mar 23;135(1-3):299-308. Epub 2017 May 23.

Center for Biological Resources & Informatics, Tokyo Institute of Technology, Yokohama, 226-8501, Japan.

The regulatory nucleotides, guanosine 5'-triphosphate 3'-diphosphate (pppGpp) and guanosine 5'-diphosphate 3'-diphosphate (ppGpp), were originally identified in Escherichia coli, and control a large set of gene expression and enzyme activities. The (p)ppGpp-dependent control of cell activities is referred to as the stringent response. A growing number of (p)ppGpp synthase/hydrolase homologs have been identified in plants, which are localized in plastids in Arabidopsis thaliana. We recently reported that the Arabidopsis mutant overproducing ppGpp in plastids showed dwarf chloroplasts, and transcript levels in the mutant plastids were significantly suppressed. Furthermore, the mutant showed more robust growth than the wild type (WT), especially under nutrient-deficient conditions, although the mechanisms are unclear. To better understand the impact of the ppGpp accumulation on plant responses to nutrient deficiency, photosynthetic activities and metabolic changes in the ppGpp-overproducing mutant were characterized here. Upon transition to the nitrogen-deficient conditions, the mutant showed reduction of ribulose 1,5-bisphosphate carboxylase/oxygenase (RubisCO) contents, and effective and maximum quantum yield of photosystem II compared with WT. The mutant also showed more obvious changes in key metabolite levels including some amino acid contents than WT; similar metabolic change is known to be critical for plants to maintain carbon-nitrogen balance in their cells. These results suggest that artificially overproducing ppGpp modulates the organelle functions that play an important role in controlling photosynthetic performance and metabolite balance during nitrogen starvation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s11120-017-0402-yDOI Listing
March 2018

Toward an understanding of the pathophysiology of clear cell carcinoma of the ovary (Review).

Oncol Lett 2013 Nov 28;6(5):1163-1173. Epub 2013 Aug 28.

Department of Obstetrics and Gynecology, Nara Medical University, Kashihara, Nara 634-8522, Japan.

Endometriosis-associated ovarian cancers demonstrate substantial morphological and genetic diversity. The transcription factor, hepatocyte nuclear factor (HNF)-1β, may be one of several key genes involved in the identity of ovarian clear cell carcinoma (CCC). The present study reviews a considerably expanded set of HNF-1β-associated genes and proteins that determine the pathophysiology of CCC. The current literature was reviewed by searching MEDLINE/PubMed. Functional interpretations of gene expression profiling in CCC are provided. Several important CCC-related genes overlap with those known to be regulated by the upregulation of HNF-1β expression, along with a lack of estrogen receptor (ER) expression. Furthermore, the genetic expression pattern in CCC resembles that of the Arias-Stella reaction, decidualization and placentation. HNF-1β regulates a subset of progesterone target genes. HNF-1β may also act as a modulator of female reproduction, playing a role in endometrial regeneration, differentiation, decidualization, glycogen synthesis, detoxification, cell cycle regulation, implantation, uterine receptivity and a successful pregnancy. In conclusion, the present study focused on reviewing the aberrant expression of CCC-specific genes and provided an update on the pathological implications and molecular functions of well-characterized CCC-specific genes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3892/ol.2013.1550DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3813717PMC
November 2013
-->