Histone Modification-Dependent Transcriptional Regulation of Defence Genes in Early Response of Arabidopsis to Spodoptera litura Attack.

Histone modification is a cellular process for transcriptional regulation. In herbivore-damaged plants, activation of genes involved in defence responses is required for antiherbivore properties, but little is known about how the chromatin remodelling system is involved. In Arabidopsis (Arabidopsis thaliana) plants responding to Spodoptera litura larvae, HAC1 and HDA6, a histone acetyltransferase and a histone deacetylase, respectively, were found here to be involved in histone H3 (Lys9; H3K9) acetylation/deacetylation at the promoter region of the plant defensin gene PDF1.

Incorporation of photosynthetically active algal chloroplasts in cultured mammalian cells towards photosynthesis in animals.

Chloroplasts are photosynthetic organelles that evolved through the endosymbiosis between cyanobacteria-like symbionts and hosts. Many studies have attempted to isolate intact chloroplasts to analyze their morphological characteristics and photosynthetic activity. Although several studies introduced isolated chloroplasts into the cells of different species, their photosynthetic activities have not been confirmed.

Plant chromosome polytenization contributes to suppression of root growth in high polyploids.

Autopolyploidization, which refers to a polyploidization via genome duplication without hybridization, promotes growth in autotetraploids, but suppresses growth in high polyploids (autohexaploids or auto-octoploids). The mechanism underlying this growth suppression (i.e.

A chromosome-level genome assembly for the amphibious plant Rorippa aquatica reveals its allotetraploid origin and mechanisms of heterophylly upon submergence.

The ability to respond to varying environments is crucial for sessile organisms such as plants. The amphibious plant Rorippa aquatica exhibits a striking type of phenotypic plasticity known as heterophylly, a phenomenon in which leaf form is altered in response to environmental factors. However, the underlying molecular mechanisms of heterophylly are yet to be fully understood.

Nuclear pore complex proteins are involved in centromere distribution.

The subnuclear distribution of centromeres is cooperatively regulated by condensin II and the linker of nucleoskeleton and cytoskeleton (LINC) complex. However, other nuclear membrane structures and nuclear proteins are probably involved in centromere dynamics and distribution. Here, we focused on the nuclear pore complex (NPC), which is known to regulate gene expression, transcription memory, and chromatin structure in addition to transport between the cytoplasm and nucleoplasm.

Complete mitochondrial and chloroplast DNA sequences of the freshwater green microalga Medakamo hakoo.

We report the complete organellar genome sequences of an ultrasmall green alga, Medakamo hakoo strain M-hakoo 311, which has the smallest known nuclear genome in freshwater green algae. Medakamo hakoo has 90.8-kb chloroplast and 36.

Chromatin dynamics and subnuclear gene positioning for transcriptional regulation.

Plants have been found to exhibit diverse characteristics and functions of chromatin organization, showing both similarities and differences to animals. It is becoming clear how chromatin organization is linked to transcriptional regulation in response to environmental stresses. Regulation of specific chromatin positions in the nuclear space is important for transcription, and the mechanisms that enable such chromatin dynamics are gradually being unveiled.

The plant nuclear lamina disassembles to regulate genome folding in stress conditions.

The nuclear lamina is a complex network of nuclear lamins and lamin-associated nuclear membrane proteins, which scaffold the nucleus to maintain structural integrity. In Arabidopsis thaliana, nuclear matrix constituent proteins (NMCPs) are essential components of the nuclear lamina and are required to maintain the structural integrity of the nucleus and specific perinuclear chromatin anchoring. At the nuclear periphery, suppressed chromatin overlapping with repetitive sequences and inactive protein-coding genes are enriched.

Novel whole-mount FISH analysis for intact root of Arabidopsis thaliana with spatial reference to 3D visualization.

Whole-mount fluorescent in situ hybridization (WM-FISH) is an effective tool to observe chromosome behavior in tissues or organs. However, it is difficult to obtain a precise spatial profile of fluorescent signals in roots using conventional WM-FISH mainly because of the severe damage caused during the processing. To address this problem, we established a novel WM-FISH analysis for intact roots of Arabidopsis thaliana and successfully obtained a precise spatial profile of nuclear size and centromere signals.

Genomic analysis of an ultrasmall freshwater green alga, Medakamo hakoo.

Ultrasmall algae have attracted the attention of biologists investigating the basic mechanisms underlying living systems. Their potential as effective organisms for producing useful substances is also of interest in bioindustry. Although genomic information is indispensable for elucidating metabolism and promoting molecular breeding, many ultrasmall algae remain genetically uncharacterized.

Two-step regulation of centromere distribution by condensin II and the nuclear envelope proteins.

The arrangement of centromeres within the nucleus differs among species and cell types. However, neither the mechanisms determining centromere distribution nor its biological significance are currently well understood. In this study, we demonstrate the importance of centromere distribution for the maintenance of genome integrity through the cytogenic and molecular analysis of mutants defective in centromere distribution.

Sustained defense response via volatile signaling and its epigenetic transcriptional regulation.

Plants perceive volatiles emitted from herbivore-damaged neighboring plants to urgently adapt or prime their defense responses to prepare for forthcoming herbivores. Mechanistically, these volatiles can induce epigenetic regulation based on histone modifications that alter the transcriptional status of defense genes, but little is known about the underlying mechanisms. To understand the roles of such epigenetic regulation of plant volatile signaling, we explored the response of Arabidopsis (Arabidopsis thaliana) plants to the volatile β-ocimene.

TBP-ASSOCIATED FACTOR 12 ortholog NOBIRO6 controls root elongation with unfolded protein response cofactor activity.

Plant root growth is indeterminate but continuously responds to environmental changes. We previously reported on the severe root growth defect of a double mutant in and () modulating the unfolded protein response (UPR). To elucidate the mechanism by which seedlings develop a short root, we obtained a series of suppressor mutants, called , for rescued root growth.

Improved clearing method contributes to deep imaging of plant organs.

Tissue clearing methods are increasingly essential for the microscopic observation of internal tissues of thick biological organs. We previously developed TOMEI, a clearing method for plant tissues; however, it could not entirely remove chlorophylls nor reduce the fluorescent signal of fluorescent proteins. Here, we developed an improved TOMEI method (iTOMEI) to overcome these limitations.

Whole-Tissue Three-Dimensional Imaging of Rice at Single-Cell Resolution.

The three-dimensional (3D) arrangement of cells in tissues provides an anatomical basis for analyzing physiological and biochemical aspects of plant and animal cellular development and function. In this study, we established a protocol for tissue clearing and 3D imaging in rice. Our protocol is based on three improvements: clearing with iTOMEI (clearing solution suitable for plants), developing microscopic conditions in which the Z step is optimized for 3D reconstruction, and optimizing cell-wall staining.

An anchoring complex recruits katanin for microtubule severing at the plant cortical nucleation sites.

Microtubules are severed by katanin at distinct cellular locations to facilitate reorientation or amplification of dynamic microtubule arrays, but katanin targeting mechanisms are poorly understood. Here we show that a centrosomal microtubule-anchoring complex is used to recruit katanin in acentrosomal plant cells. The conserved protein complex of Msd1 (also known as SSX2IP) and Wdr8 is localized at microtubule nucleation sites along the microtubule lattice in interphase Arabidopsis cells.

A live imaging system to analyze spatiotemporal dynamics of RNA polymerase II modification in Arabidopsis thaliana.

Spatiotemporal changes in general transcription levels play a vital role in the dynamic regulation of various critical activities. Phosphorylation levels at Ser2 in heptad repeats within the C-terminal domain of RNA polymerase II, representing the elongation form, is an indicator of transcription. However, rapid transcriptional changes during tissue development and cellular phenomena are difficult to capture in living organisms.

Thiazoline-related innate fear stimuli orchestrate hypothermia and anti-hypoxia via sensory TRPA1 activation.

Thiazoline-related innate fear-eliciting compounds (tFOs) orchestrate hypothermia, hypometabolism, and anti-hypoxia, which enable survival in lethal hypoxic conditions. Here, we show that most of these effects are severely attenuated in transient receptor potential ankyrin 1 (Trpa1) knockout mice. TFO-induced hypothermia involves the Trpa1-mediated trigeminal/vagal pathways and non-Trpa1 olfactory pathway.

Common architectures in cyanobacteria Prochlorococcus cells visualized by X-ray diffraction imaging using X-ray free electron laser.

Visualization of intracellular structures and their spatial organization inside cells without any modification is essential to understand the mechanisms underlying the biological functions of cells. Here, we investigated the intracellular structure of cyanobacteria Prochlorococcus in the interphase by X-ray diffraction imaging using X-ray free-electron laser. A number of diffraction patterns from single cells smaller than 1 µm in size were collected with high signal-to-noise ratio with a resolution of up to 30 nm.

SQAP, an acyl sulfoquinovosyl derivative, suppresses expression of histone deacetylase and induces cell death of cancer cells under hypoxic conditions.

Sulfoglycolipid, SQAP, is a radiosensitizing agent that makes tumor cells more sensitive to radiation therapy. A previous study revealed that SQAP induced the degradation of hypoxia-inducible factor-1α (HIF-1α) and inhibited angiogenesis in a hepatoma model mouse. Herein, we examined the biological activities of SQAP against hepatocarcinoma cells under low oxygen conditions.

Visualization of extracellular vesicles in the regenerating caudal fin blastema of zebrafish using in vivo electroporation.

Zebrafish have high regenerative ability in several organs including the fin. Although various mechanisms underlying fin regeneration have been revealed, some mechanisms remain to be elucidated. Recently, extracellular vesicles (EVs) have been the focus of research with regard to their role in cell-to-cell communication.