Ring/U-Box Protein AtUSR1 Functions in Promoting Leaf Senescence Through JA Signaling Pathway in Arabidopsis

Leaf senescence is regulated by a large number of internal and environmental factors. Here, we report that AtUSR1 (U-box Senescence Related 1) which encodes a plant Ring/U-box protein, is involved in age-dependent and dark-induced leaf senescence in Arabidopsis. Expression of AtUSR1 gene in leaves was up-regulated in darkness and during aging. Plants of usr1, an AtUSR1 gene knock-down mutant, showed a significant delay in age-dependent and dark-induced leaf senescence and the delayed senescence phenotype was rescued when the AtUSR1 gene was transferred back to the mutant plants. Meanwhile, overexpression of AtUSR1 caused accelerated leaf senescence. Furthermore, the role of AtUSR1 in regulating leaf senescence is related to MYC2-mediuated jasmonic acid (JA) signaling pathway. MeJA treatments promoted the accumulation of AtUSR1 transcripts and this expression activation was dependent on the function of MYC2, a key transcription factor in JA signaling. Dual-luciferase assay results indicated that MYC2 promoted the expression of AtUSR1. Overexpression of AtUSR1 in myc2 mutant plants showed precocious senescence, while myc2 mutation alone caused a delay in leaf senescence, suggesting that AtUSR1 functions downstream to MYC2 in the JA signaling pathway in promoting leaf senescence.

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The NAC transcription factor ANAC046 is a positive regulator of chlorophyll degradation and senescence in Arabidopsis leaves

Scientific Reports ◽

10.1038/srep23609 ◽

2016 ◽

Vol 6 (1) ◽

Cited By ~ 60

Author(s):

Chihiro Oda-Yamamizo ◽

Nobutaka Mitsuda ◽

Shingo Sakamoto ◽

Daisuke Ogawa ◽

Masaru Ohme-Takagi ◽

...

Keyword(s):

Transcription Factor ◽

Transgenic Plants ◽

Leaf Senescence ◽

Loss Of Function ◽

Pheophorbide A ◽

Delayed Senescence ◽

Positive Regulator ◽

Catabolic Genes ◽

Senescence Associated Genes ◽

Senescence Phenotype

Abstract Chlorophyll (Chl) degradation occurs during leaf senescence, embryo degreening, bud breaking, and fruit ripening. The Chl catabolic pathway has been intensively studied and nearly all the enzymes involved are identified and characterized; however, the molecular regulatory mechanisms of this pathway are largely unknown. In this study, we performed yeast one-hybrid screening using a transcription factor cDNA library to search for factors controlling the expression of Chl catabolic genes. We identified ANAC046 as a common regulator that directly binds to the promoter regions of NON-YELLOW COLORING1, STAY-GREEN1 (SGR1), SGR2, and PHEOPHORBIDE a OXYGENASE. Transgenic plants overexpressing ANAC046 exhibited an early-senescence phenotype and a lower Chl content in comparison with the wild-type plants, whereas loss-of-function mutants exhibited a delayed-senescence phenotype and a higher Chl content. Microarray analysis of ANAC046 transgenic plants showed that not only Chl catabolic genes but also senescence-associated genes were positively regulated by ANAC046. We conclude that ANAC046 is a positive regulator of Arabidopsis leaf senescence and exerts its effect by controlling the expression of Chl catabolic genes and senescence-associated genes.

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The leaf senescence-promoting transcription factor AtNAP activates its direct target gene CYTOKININ OXIDASE 3 to facilitate senescence processes by degrading cytokinins

Molecular Horticulture ◽

10.1186/s43897-021-00017-6 ◽

2021 ◽

Vol 1 (1) ◽

Author(s):

Youzhen Hu ◽

Bin Liu ◽

Huazhong Ren ◽

Liping Chen ◽

Christopher B. Watkins ◽

...

Keyword(s):

Transcription Factor ◽

Leaf Senescence ◽

Plant Hormones ◽

Cytokinin Oxidase ◽

In Planta ◽

Delayed Senescence ◽

Lateral Bud ◽

Direct Target Gene ◽

Fountain Of Youth ◽

Senescence Phenotype

AbstractCytokinins (CKs) are a class of adenine-derived plant hormones that plays pervasive roles in plant growth and development including cell division, morphogenesis, lateral bud outgrowth, leaf expansion and senescence. CKs as a “fountain of youth” prolongs leaf longevity by inhibiting leaf senescence, and therefore must be catabolized for senescence to occur. AtNAP, a senescence-specific transcription factor has a key role in promoting leaf senescence. The role of AtNAP in regulating CK catabolism is unknown. Here we report the identification and characterization of AtNAP-AtCKX3 (cytokinin oxidase 3) module by which CKs are catabolized during leaf senescence in Arabidopsis. Like AtNAP, AtCKX3 is highly upregulated during leaf senescence. When AtNAP is chemically induced AtCKX3 is co-induced; and when AtNAP is knocked out, the expression of AtCKX3 is abolished. AtNAP physically binds to the cis element of the AtCKX3 promoter to direct its expression as revealed by yeast one-hybrid assays and in planta experiments. Leaves of the atckx3 knockout lines have higher CK concentrations and a delayed senescence phenotype compared with those of WT. In contrast, leaves with inducible expression of AtCKX3 have lower CK concentrations and exhibit a precocious senescence phenotype compared with WT. This research reveals that AtNAP transcription factor˗AtCKX3 module regulates leaf senescence by connecting two antagonist plant hormones abscisic acid and CKs.

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A WRKY transcription factor, TaWRKY42-B, facilitates initiation of leaf senescence by promoting jasmonic acid biosynthesis

BMC Plant Biology ◽

10.1186/s12870-020-02650-7 ◽

2020 ◽

Vol 20 (1) ◽

Author(s):

Ming-Ming Zhao ◽

Xiao-Wen Zhang ◽

Yong-Wei Liu ◽

Ke Li ◽

Qi Tan ◽

...

Keyword(s):

Leaf Senescence ◽

Expression Profiles ◽

Functional Characterization ◽

Wrky Transcription Factor ◽

Positive Role ◽

Environmental Signals ◽

Source To Sink ◽

Age Dependent ◽

Functional Investigation

Abstract Background Leaf senescence comprises numerous cooperative events, integrates environmental signals with age-dependent developmental cues, and coordinates the multifaceted deterioration and source-to-sink allocation of nutrients. In crops, leaf senescence has long been regarded as an essential developmental stage for productivity and quality, whereas functional characterization of candidate genes involved in the regulation of leaf senescence has, thus far, been limited in wheat. Results In this study, we analyzed the expression profiles of 97 WRKY transcription factors (TFs) throughout the progression of leaf senescence in wheat and subsequently isolated a potential regulator of leaf senescence, TaWRKY42-B, for further functional investigation. By phenotypic and physiological analyses in TaWRKY42-B-overexpressing Arabidopsis plants and TaWRKY42-B-silenced wheat plants, we confirmed the positive role of TaWRKY42-B in the initiation of developmental and dark-induced leaf senescence. Furthermore, our results revealed that TaWRKY42-B promotes leaf senescence mainly by interacting with a JA biosynthesis gene, AtLOX3, and its ortholog, TaLOX3, which consequently contributes to the accumulation of JA content. In the present study, we also demonstrated that TaWRKY42-B was functionally conserved with AtWRKY53 in the initiation of age-dependent leaf senescence. Conclusion Our results revealed a novel positive regulator of leaf senescence, TaWRKY42-B, which mediates JA-related leaf senescence via activation of JA biosynthesis and has the potential to be a target gene for molecular breeding in wheat.

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MiR-21-3p Promotes Hepatocellular Carcinoma Progression via SMAD7/YAP1 Regulation

Frontiers in Oncology ◽

10.3389/fonc.2021.642030 ◽

2021 ◽

Vol 11 ◽

Author(s):

Yinghui Hong ◽

Mingliang Ye ◽

Fan Wang ◽

Jun Fang ◽

Chun Wang ◽

...

Keyword(s):

Hepatocellular Carcinoma ◽

Overall Survival ◽

Signaling Pathway ◽

Negative Regulator ◽

Epigenetic Mechanism ◽

Luciferase Assay ◽

Rat Models ◽

Cancer Pathogenesis ◽

Tumor Stages

BackgroundHepatocellular carcinoma (HCC) remains a major global health burden due to its high prevalence and mortality. Emerging evidence reveals that microRNA (miRNA) plays a vital role in cancer pathogenesis and is widely involved in the regulation of signaling pathways via their targeting of downstream genes. MiR-21-3p, a liver-enriched miRNA, and SMAD7, the negative regulator of the TGF-β signaling pathway, likely exert a vital influence on HCC progression.AimsHere, we explore the role of the miR-21-3p-SMAD7/YAP1 axis on HCC pathogenesis.MethodsMiRNA microarray analysis was performed for miRNA screening. The dual-luciferase assay was adopted for target verification. Expression of miRNA and related genes were quantified via qRT-PCR, western blotting, and immunohistochemical staining. Flow cytometry and the transwell migration assay were used to detail cell apoptosis, invasion and metastases. Rat models were established to explore the role of the miR-21-3p-SMAD7/YAP1 axis in hepatocarcinogenesis. Bioinformatics analysis was conducted for exploring genes of clinical significance.ResultsMiR-21-3p levels were found to be significantly elevated in hepatocellular carcinoma and indicate poor overall survival. High miR-21-3p levels were associated with advanced tumor stages (P = 0.029), in particular T staging (P = 0.026). Low SMAD7/high YAP1 levels were confirmed in both HCC and rat models with advanced liver fibrosis and cirrhosis. Besides, SMAD7 was demonstrated to be the direct target of miR-21-3p. The effect of MiR-21-3p on tumor phenotypes and YAP1 upregulation could be partly reversed via the restoration of SMAD7 expression in HCC cell lines. Overexpression of YAP1 after miR-21-3p upregulation promoted expression of nuclear transcription effector connective tissue growth factor. Co-survival analysis indicated that lower miR-21-3p/higher SMAD7 (P = 0.0494) and lower miR-21-3p/lower YAP1 (P = 0.0379) group patients had better overall survival rates. Gene Set Variation Analysis revealed that gene sets related to miR-21-3p and SMAD7 were significantly associated with the TGF-β signaling pathway in HCC.ConclusionMiR-21-3p promotes migration and invasion of HCC cells and upregulation of YAP1 expression via direct inhibition of SMAD7, underscoring a major epigenetic mechanism in the pathogenesis of HCC.

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MicroRNA-1271-5p inhibits the tumorigenesis of ovarian cancer through targeting E2F5 and negatively regulates the mTOR signaling pathway

10.21203/rs.3.rs-17270/v1 ◽

2020 ◽

Author(s):

Qin Li ◽

Junyu Shi ◽

Xiaoli Xu

Keyword(s):

Ovarian Cancer ◽

Signaling Pathway ◽

Poor Prognosis ◽

Mtor Signaling ◽

Luciferase Assay ◽

Migration And Invasion ◽

Mtor Signaling Pathway ◽

Direct Target ◽

The Relationship

Abstract Background: MicroRNA-1271-5p (miR-1271-5p) has been reported to participate in the progression of many human cancers. However, the role of miR-1271-5p still remains unclear in ovarian cancer (OC). Therefore, we explored the effect of miR-1271-5p on the development of OC in present study. Methods: We measured the miR-1271-5p expression via the qRT-PCR assay. Then the function of miR-1271-5p was analyzed through MTT and Transwell assays. The relationship among miR-1271-5p and E2F5 was verified by dual luciferase assay. The protein expression levels were examined through western blot.Results: MiR-1271-5p was downregulated in OC tissues which predicted poor prognosis of OC patients. Moreover, E2F5 was a direct target of miR-1271-5p in OC. And miR-1271-5p suppressed cell proliferation, migration and invasion in OC through targeting E2F5. Furthermore, E2F5 was upregulated in OC tissues which predicted poor prognosis of OC patients. Besides that, miR-1271-5p suppressed EMT and mTOR pathway in OC. Conclusion: MiR-1271-5p inhibited the tumorigenesis of OC through targeting E2F5 and negatively regulated the mTOR signaling pathway.

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chi-miR-487b-3p Inhibits Goat Myoblast Proliferation and Differentiation by Targeting IRS1 through the IRS1/PI3K/Akt Signaling Pathway

International Journal of Molecular Sciences ◽

10.3390/ijms23010115 ◽

2021 ◽

Vol 23 (1) ◽

pp. 115

Author(s):

Ming Lyu ◽

Xu Wang ◽

Xiangyu Meng ◽

Hongrun Qian ◽

Qian Li ◽

...

Keyword(s):

Signaling Pathway ◽

Muscle Development ◽

Akt Signaling ◽

Significant Inhibition ◽

Luciferase Assay ◽

Akt Signaling Pathway ◽

Small Noncoding Rnas ◽

Proliferation And Differentiation ◽

Myoblast Proliferation

MicroRNAs (miRNAs) are endogenously expressed small noncoding RNAs and play critical roles in the regulation of post-transcriptional gene expression. Our previous study uncovered that chi-miR-487b-3p is widespread in different goat tissues, which is significantly higher in muscle, especially in lamb. Here, we demonstrate the role of chi-miR-487b-3p as a myogenic miRNA that regulates skeletal muscle development. chi-miR-487b-3p overexpression was demonstrated to significantly inhibit goat myoblast proliferation and differentiation, whereas chi-miR-487b-3p inhibition resulted in the opposite effects. Next, chi-miR-487b-3p was predicted to target the 3′UTR of insulin receptor substrate 1 (IRS1) gene by Target-Scan and miRDB. The results of dual-luciferase assay, RT-qPCR, and western blot all confirmed that IRS1 might be a direct target of chi-miR-487b-3p as its expression was negatively regulated by chi-miR-487b-3p. siRNA silencing of IRS1 further demonstrated significant inhibition on goat myoblast proliferation and differentiation, confirming the effect of IRS1 downregulation by chi-miR-487b-3p in myogenesis. In addition, chi-miR-487b-3p knockout goat myoblast clones were generated using CRISPR/Cas9 technology, and we further illustrated that chi-miR-487b-3p regulates goat myoblast growth through the PI3K/Akt signaling pathway by targeting IRS1. Collectively, our work demonstrated that chi-miR-487b-3p is a potent inhibitor of skeletal myogenesis and provided new insights into the mechanisms of miRNA on the regulation of goat growth.

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The transcription factor KLF14 regulates macrophage glycolysis and immune function by inhibiting HK2 in sepsis

Cellular and Molecular Immunology ◽

10.1038/s41423-021-00806-5 ◽

2022 ◽

Author(s):

Yuan Yuan ◽

Guangjian Fan ◽

Yuqi Liu ◽

Lu Liu ◽

Tong Zhang ◽

...

Keyword(s):

Transcription Factor ◽

Immune Function ◽

Signaling Pathway ◽

Inflammatory Cytokines ◽

Host Response ◽

Targeted Therapeutics ◽

Inflammatory Signaling ◽

Regulation Of Glycolysis ◽

Shed Light

AbstractSepsis is a heterogeneous syndrome induced by a dysregulated host response to infection. Glycolysis plays a role in maintaining the immune function of macrophages, which is crucial for severely septic patients. However, how the pathways that link glycolysis and macrophages are regulated is still largely unknown. Here, we provide evidence to support the function of KLF14, a novel Krüppel-like transcription factor, in the regulation of glycolysis and the immune function of macrophages during sepsis. KLF14 deletion led to significantly increased mortality in lethal models of murine endotoxemia and sepsis. Mechanistically, KLF14 decreased glycolysis and the secretion of inflammatory cytokines by macrophages by inhibiting the transcription of HK2. In addition, we confirmed that the expression of KLF14 was upregulated in septic patients. Furthermore, pharmacological activation of KLF14 conferred protection against sepsis in mice. These findings uncover a key role of KLF14 in modulating the inflammatory signaling pathway and shed light on the development of KLF14-targeted therapeutics for sepsis.

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USP18 Mediates Interferon Resistance of Dengue Virus Infection

Frontiers in Microbiology ◽

10.3389/fmicb.2021.682380 ◽

2021 ◽

Vol 12 ◽

Author(s):

Haiyan Ye ◽

Xiaoqiong Duan ◽

Min Yao ◽

Lan Kang ◽

Yujia Li ◽

...

Keyword(s):

Dengue Virus ◽

Western Blot ◽

Signaling Pathway ◽

Hela Cells ◽

Denv Infection ◽

Luciferase Assay ◽

Type I ◽

Qrt Pcr ◽

Stat Signaling

Previous studies demonstrated that dengue virus (DENV) infection developed resistance to type-I interferons (IFNα/β). The underlying mechanism remains unclear. USP18 is a negative regulator of IFNα/β signaling, and its expression level is significantly increased following DENV infection in cell lines and patients’ blood. Our previous study revealed that increased USP18 expression contributed to the IFN-α resistance of Hepatitis C Virus (HCV). However, the role of USP18 in DENV replication and resistance to IFN-α is elusive. In this current study, we aimed to explore the role of USP18 in DENV-2 replication and resistance to IFN-α. The level of USP18 was up-regulated by plasmid transfection and down-regulated by siRNA transfection in Hela cells. USP18, IFN-α, IFN-β expression, and DENV-2 replication were monitored by qRT-PCR and Western blot. The activation of the Jak/STAT signaling pathway was assessed at three levels: p-STAT1/p-STAT2 (Western blot), interferon-stimulated response element (ISRE) activity (Dual-luciferase assay), and interferon-stimulated genes (ISGs) expression (qRT-PCR). Our data showed that DENV-2 infection increased USP18 expression in Hela cells. USP18 overexpression promoted DENV-2 replication, while USP18 silence inhibited DENV-2 replication. Silence of USP18 potentiated the anti-DENV-2 activity of IFN-α through activation of the IFN-α-mediated Jak/STAT signaling pathway as shown by increased expression of p-STAT1/p-STAT2, enhanced ISRE activity, and elevated expression of some ISGs. Our data indicated that USP18 induced by DENV-2 infection is a critical host factor utilized by DENV-2 to confer antagonism on IFN-α.

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Necrotrophic Pathogens Use the Salicylic Acid Signaling Pathway to Promote Disease Development in Tomato

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-07-12-0187-r ◽

2012 ◽

Vol 25 (12) ◽

pp. 1584-1593 ◽

Cited By ~ 72

Author(s):

Taha Abd El Rahman ◽

Mohamed El Oirdi ◽

Rocio Gonzalez-Lamothe ◽

Kamal Bouarab

Keyword(s):

Transcription Factor ◽

Salicylic Acid ◽

Signaling Pathway ◽

Proteinase Inhibitors ◽

Alternaria Solani ◽

Disease Development ◽

Necrotrophic Pathogen ◽

Biotrophic Pathogens ◽

Ja Signaling ◽

Sa Signaling

Plants use different immune pathways to combat pathogens. The activation of the jasmonic acid (JA)-signaling pathway is required for resistance against necrotrophic pathogens; however, to combat biotrophic pathogens, the plants activate mainly the salicylic acid (SA)-signaling pathway. SA can antagonize JA signaling and vice versa. NPR1 (noninducible pathogenesis-related 1) is considered a master regulator of SA signaling. NPR1 interacts with TGA transcription factors, ultimately leading to the activation of SA-dependent responses. SA has been shown to promote disease development caused by the necrotrophic pathogen Botrytis cinerea through NPR1, by suppressing the expression of two JA-dependent defense genes, proteinase inhibitors I and II. We show here that the transcription factor TGA1.a contributes to disease development caused by B. cinerea in tomato by suppressing the expression of proteinase inhibitors I and II. Finally, we present evidence that the SA-signaling pathway contributes to disease development caused by another necrotrophic pathogen, Alternaria solani, in tomato. Disease development promoted by SA through NPR1 requires the TGA1.a transcription factor. These data highlight how necrotrophs manipulate the SA-signaling pathway to promote their disease in tomato.

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