A Bacterial Platform for Studying Ubiquitination Cascades Anchored by SCF-Type E3 Ubiquitin Ligases.

Ubiquitination is one of the most important post-translational modifications in eukaryotes. The ubiquitination cascade includes ubiquitin-activating enzymes (E1), ubiquitin-conjugating enzymes (E2), and ubiquitin ligases (E3). The E3 ligases, responsible for substrate recognition, are the most abundant and varied proteins in the cascade and the most studied.

Significance of NatB-mediated N-terminal acetylation of auxin biosynthetic enzymes in maintaining auxin homeostasis in Arabidopsis thaliana.

The auxin IAA (Indole-3-acetic acid) plays key roles in regulating plant growth and development, which depends on an intricate homeostasis that is determined by the balance between its biosynthesis, metabolism and transport. YUC flavin monooxygenases catalyze the rate-limiting step of auxin biosynthesis via IPyA (indole pyruvic acid) and are critical targets in regulating auxin homeostasis. Despite of numerous reports on the transcriptional regulation of YUC genes, little is known about those at the post-translational protein level.

The roles of epigenetic modifications in the regulation of auxin biosynthesis.

Auxin is one of the most important plant growth regulators of plant morphogenesis and response to environmental stimuli. Although the biosynthesis pathway of auxin has been elucidated, the mechanisms regulating auxin biosynthesis remain poorly understood. The transcription of auxin biosynthetic genes is precisely regulated by complex signaling pathways.

Peptides-based therapeutics: Emerging potential therapeutic agents for COVID-19.

SARS-CoV-2 is a positive-sense RNA virus and it is the causative agent of the global COVID-19 outbreak. COVID-19 is similar to the previous outbreaks for instance SARS in 2002-2003 and MERS in 2012. As the peptides have many advantages, peptide-based therapeutics might be one of the possible ways in the development of COVID-19 specific drugs.

Stablization of ACOs by NatB mediated N-terminal acetylation is required for ethylene homeostasis.

N-terminal acetylation (NTA) is a highly abundant protein modification catalyzed by N-terminal acetyltransferases (NATs) in eukaryotes. However, the plant NATs and their biological functions have been poorly explored. Here we reveal that loss of function of CKRC3 and NBC-1, the auxiliary subunit (Naa25) and catalytic subunit (Naa20) of Arabidopsis NatB, respectively, led to defects in skotomorphogenesis and triple responses of ethylene.

Cytokinin-Controlled Gradient Distribution of Auxin in Root Tip.

The plant root is a dynamic system, which is able to respond promptly to external environmental stimuli by constantly adjusting its growth and development. A key component regulating this growth and development is the finely tuned cross-talk between the auxin and cytokinin phytohormones. The gradient distribution of auxin is not only important for the growth and development of roots, but also for root growth in various response.

Function of histone H2B monoubiquitination in transcriptional regulation of auxin biosynthesis in Arabidopsis.

The auxin IAA is a vital plant hormone in controlling growth and development, but our knowledge about its complicated biosynthetic pathways and molecular regulation are still limited and fragmentary. cytokinin induced root waving 2 (ckrw2) was isolated as one of the auxin-deficient mutants in a large-scale forward genetic screen aiming to find more genes functioning in auxin homeostasis and/or its regulation. Here we show that CKRW2 is identical to Histone Monoubiquitination 1 (HUB1), a gene encoding an E3 ligase required for histone H2B monoubiquitination (H2Bub1) in Arabidopsis.

The Arabidopsis R-SNARE VAMP714 is essential for polarisation of PIN proteins and auxin responses.

The plant hormone auxin and its directional intercellular transport play a major role in diverse aspects of plant growth and development. The establishment of auxin gradients requires the asymmetric distribution of members of the auxin efflux carrier PIN-FORMED (PIN) protein family to the plasma membrane. An endocytic pathway regulates the recycling of PIN proteins between the plasma membrane and endosomes, providing a mechanism for dynamic localisation.

Vesicle Transport in Plants: A Revised Phylogeny of SNARE Proteins.

Communication systems within and between plant cells involve the transfer of ions and molecules between compartments, and are essential for development and responses to biotic and abiotic stresses. This in turn requires the regulated movement and fusion of membrane systems with their associated cargo. Recent advances in genomics has provided new resources with which to investigate the evolutionary relationships between membrane proteins across plant species.

Anti-proliferation effects of ethanolic extracts from Sophora moorcroftiana seeds on human hepatocarcinoma HepG2 cell line.

Previous studies have shown that the ethanolic extracts from Sophora moorcroftiana seeds (ee-Sms) have in vitro anticancer properties. The anti-proliferation effects of ee-Sms on HepG2 cells were assessed by MTT assay and cell cycle analysis. Total cell proteins were separated by two-dimensional electrophoresis (2-DE), and protein spots with more than two-fold difference were analysed by MALDI-TOF/TOF-MS.

Functional roles of Arabidopsis CKRC2/YUCCA8 gene and the involvement of PIF4 in the regulation of auxin biosynthesis by cytokinin.

Auxin and cytokinin (CK) are both important hormones involved in many aspects of plant growth and development. However, the details of auxin biosynthesis and the interaction between auxin and CK are still unclear. Isolation and characterization of an auxin deficient mutant cytokinin induced root curling 2 (ckrc2) in this work reveal that CKRC2 encodes a previously identified member of YUCCA (YUC) flavin monooxygenase-like proteins (YUC8).

Forward genetic screen for auxin-deficient mutants by cytokinin.

Identification of mutants with impairments in auxin biosynthesis and dynamics by forward genetic screening is hindered by the complexity, redundancy and necessity of the pathways involved. Furthermore, although a few auxin-deficient mutants have been recently identified by screening for altered responses to shade, ethylene, N-1-naphthylphthalamic acid (NPA) or cytokinin (CK), there is still a lack of robust markers for systematically isolating such mutants. We hypothesized that a potentially suitable phenotypic marker is root curling induced by CK, as observed in the auxin biosynthesis mutant CK-induced root curling 1 / tryptophan aminotransferase of Arabidopsis 1 (ckrc1/taa1).

Frequent problems and their resolutions by using thermal asymmetric interlaced PCR (TAIL-PCR) to clone genes in T-DNA tagged mutants.

T-DNA insertional mutagenesis is a powerful tool in functional genomics research. Previous studies have developed thermal asymmetric interlaced polymerase chain reaction (TAIL-PCR) as an efficient strategy in isolation of DNA sequences adjacent to known sequences in T-DNA tagged mutants. However, a number of problems are encountered when attempts are made to clone flanking sequences in T-DNA tagged mutants.

Functional roles of three cutin biosynthetic acyltransferases in cytokinin responses and skotomorphogenesis.

Cytokinins (CKs) regulate plant development and growth via a two-component signaling pathway. By forward genetic screening, we isolated an Arabidopsis mutant named grow fast on cytokinins 1 (gfc1), whose seedlings grew larger aerial parts on MS medium with CK. gfc1 is allelic to a previously reported cutin mutant defective in cuticular ridges (dcr).

Combination of cytokinin and auxin induces apoptosis, cell cycle progression arrest and blockage of the Akt pathway in HeLa cells.

Plant cytokinins and auxins have recently been proposed as novel cancer therapies, which proceed via different mechanisms; however, their combined use has not been investigated. To the best of our knowledge, the present study was the first to show that the cytokinin ortho-methoxytopolin-riboside (MeoTR) strongly inhibited the proliferation of HeLa cells, the effect of which was synergistically enhanced by auxin indole-3-acetic acid (IAA), while IAA demonstrated to have no cytotoxic effects on cells. MeoTR was found to activate intrinsic and extrinsic caspase-dependent pathways, and IAA potentiated this activation.

Involvement of secondary messengers and small organic molecules in auxin perception and signaling.

Auxin is a major phytohormone involved in most aspects of plant growth and development. Generally, auxin is perceived by three distinct receptors: TRANSPORT INHIBITOR RESISTANT1-Auxin/INDOLE ACETIC ACID, S-Phase Kinase-Associated Protein 2A and AUXIN-BINDING PROTEIN1. The auxin perception is regulated by a variety of secondary messenger molecules, including nitric oxide, reactive oxygen species, calcium, cyclic GMP, cyclic AMP, inositol triphosphate, diacylglycerol and by physiological pH.

Mechanism of apoptotosis induced by ortho-topolin riboside in human hepatoma cell line SMMC-7721.

The naturally occurring cytokinin, ortho-topolin riboside (oTR), has been recently reported to have a strong anticancer effect. However, the molecular mechanism has not been elucidated. From our research we found that oTR strongly inhibited the proliferation of SMMC-7721 cells inducing apoptosis.

Expression patterns of two Arabidopsis endo-beta-1,4-glucanase genes (At3g43860, At4g39000) in reproductive development.

Endo-beta-1,4-D-glucanases (EGases) are a widespread and vital group of glycosyl hydrolases that generally break the beta-1,4-glucosyl linkages. Studies of plant EGases have mainly been concentrated on vegetative growth, while little is currently known about their role in reproductive processes. Using the GUS reporter aided analysis of promoter activities, we identified the expression patterns of two putative Arabidopsis EGases genes (At3g43860 and At4g39000) whose promoters conferred specific localization of the GUS activity in reproductive organs.

Functional characterization of the CKRC1/TAA1 gene and dissection of hormonal actions in the Arabidopsis root.

Cytokinin (CK) influences many aspects of plant growth and development, and its function often involves intricate interactions with other phytohormones such as auxin and ethylene. However, the molecular mechanisms underlying the role of CK and its interactions with other growth regulators are still poorly understood. Here we describe the isolation and characterization of the Arabidopsis CK-induced root curling 1 (ckrc1) mutant.

Developmental changes in DNA methylation of pollen mother cells of David lily during meiotic prophase I.

Epigenetic marks in the form of DNA methylation are involved in the development of germ cells and are important in the maintenance of fertility. However, the controlling system of the on-off switch for DNA methylation largely remains unclear. In this study, the extent of cytosine methylation during the meiotic prophase I in David lily is assessed using high pressure liquid chromatography to evaluate the DNA methylation rates.

Microfilament dynamics is required for root growth under alkaline stress in Arabidopsis.

The microfilament (MF) cytoskeleton has crucial functions in plant development. Recent studies have revealed the function of MFs in diverse stress response. Alkaline stress is harmful to plant growth; however, it remains unclear whether the MFs play a role in alkaline stress.

MORPHEUS' MOLECULE1 is required to prevent aberrant RNA transcriptional read-through in Arabidopsis.

Several pathways function to remove aberrant mRNA in eukaryotic cells; however, the exact mechanisms underlying the restriction of aberrant mRNA transcription are poorly understood. In this study, we found that MORPHEUS' MOLECULE1 (MOM1) is a key component of this regulatory machinery. The Arabidopsis (Arabidopsis thaliana) mom1-44 mutation was identified by luciferase imaging in transgenic plants harboring a cauliflower mosaic virus 35S promoter-LUCIFERASE transgene lacking the 3'-untranslated region.

Arabidopsis cockayne syndrome A-like proteins 1A and 1B form a complex with CULLIN4 and damage DNA binding protein 1A and regulate the response to UV irradiation.

In plants, as in animals, DNA is constantly subject to chemical modification. UV-B irradiation is a major genotoxic agent and has significant effects on plant growth and development. Through forward genetic screening, we identified a UV-B-sensitive mutant (csaat1a-3) in Arabidopsis thaliana, in which expression of CSAat1A, encoding a Cockayne Syndrome A-like protein, is reduced due to insertion of a T-DNA in the promoter region.

Development and function of central cell in angiosperm female gametophyte.

The central cell characterizes the angiosperm female gametophyte (embryo sac or megagametophyte) in that it directly participates in "double fertilization" to initiate endosperm development, a feature distinguishing angiosperm from all other plant taxa. Polygonum-type central cell is a binucleate cell that, upon fertilization with one of the two sperm cells, forms triploid endosperm to nourish embryo development. Although the formation and the structure of central cell have well been elucidated, the molecular mechanisms for its specification and development remain largely unknown.