scholarly journals Arabidopsis SIGMA FACTOR BINDING PROTEIN1 (SIB1) and SIB2 inhibit WRKY75 function in abscisic acid-mediated leaf senescence and seed germination

2021 ◽  
Author(s):  
Haiyan Zhang ◽  
Liping Zhang ◽  
Yunrui Ji ◽  
Yifen Jing ◽  
Lanxin Li ◽  
...  
Keyword(s):  
Abscisic Acid ◽  
Seed Germination ◽  
Leaf Senescence ◽  
Chromatin Immunoprecipitation ◽  
Sigma Factor ◽  
Dependent Manner ◽  
Negative Regulators ◽  
Factor Binding ◽  
Physiological Processes ◽  
Increased Sensitivity

Abstract The plant-specific VQ gene family participates in diverse physiological processes but little information is available on their role in leaf senescence. Here, we show that the VQ motif-containing proteins, Arabidopsis SIGMA FACTOR BINDING PROTEIN1 (SIB1) and SIB2 are negative regulators of abscisic acid (ABA)-mediated leaf senescence. Loss of SIB1 and SIB2 function resulted in increased sensitivity of ABA-induced leaf senescence. In contrast, overexpression of SIB1 significantly delayed this process. Moreover, biochemical studies revealed that SIBs interact with WRKY75 transcription factor. Loss of WRKY75 function decreased sensitivity to ABA-induced leaf senescence, while overexpression of WRKY75 significantly accelerated this process. Chromatin immunoprecipitation assays revealed that WRKY75 directly binds to the promoters of GOLDEN 2-LIKE1(GLK1) and GLK2, to repress their expression. SIBs repress the transcriptional function of WRKY75 and negatively regulate ABA-induced leaf senescence in a WRKY75-dependent manner. In contrast, WRKY75 positively modulates ABA-mediated leaf senescence in a GLK-dependent manner. In addition, SIBs inhibit WRKY75 function in ABA-mediated seed germination. These results demonstrate that SIBs can form a complex with WRKY75 to regulate ABA-mediated leaf senescence and seed germination.

scholarly journals Methionine synthase 1 provides methionine for activation of the GLR3.5 Ca2+ channel and regulation of germination in Arabidopsis

2019 ◽  
Vol 71 (1) ◽  
pp. 178-187 ◽  
Author(s):  
Chuanli Ju ◽  
Dongdong Kong ◽  
Yuree Lee ◽  
Gege Ge ◽  
Yanan Song ◽  
...  
Keyword(s):  
Abscisic Acid ◽  
Seed Germination ◽  
Developmental Process ◽  
Calcium Influx ◽  
Physiological Role ◽  
Cellular Mechanism ◽  
Methionine Synthase ◽  
Dependent Manner ◽  
Shed Light ◽  
Ca2 Channels

Abstract Seed germination is a developmental process regulated by numerous internal and external cues. Our previous studies have shown that calcium influx mediated by the Arabidopsis glutamate receptor homolog 3.5 (AtGLR3.5) modulates the expression of the ABSCISIC ACID INSENSITIVE 4 (ABI4) transcription factor during germination and that L-methionine (L-Met) activates AtGLR3.1/3.5 Ca2+ channels in guard cells. However, it is not known whether L-Met participates in regulation of germination and what cellular mechanism is responsible for Met production during germination. Here, we describe Arabidopsis methionine synthase 1 (AtMS1), which acts in the final step of Met biosynthesis, synthesizes the Met required for the activation of AtGLR3.5 Ca2+ channels whose expression is up-regulated during germination, leading to the regulation of seed germination. We show that exogenous L-Met promotes germination in an AtGRL3.5-dependent manner. We also demonstrate that L-Met directly regulates the AtGLR3.5-mediated increase in cytosolic Ca2+ level in seedlings. We provide pharmacological and genetic evidence that Met synthesized via AtMS1 acts upstream of the AtGLR3.5-mediated Ca2+ signal and regulates the expression of ABI4, a major regulator in the abscisic acid response in seeds. Overall, our results link AtMS1, L-Met, the AtGLR3.5 Ca2+ channel, Ca2+ signals, and ABI4, and shed light on the physiological role and molecular mechanism of L-Met in germination.

scholarly journals Rnf8 deficiency impairs class switch recombination, spermatogenesis, and genomic integrity and predisposes for cancer

2010 ◽  
Vol 207 (5) ◽  
pp. 983-997 ◽  
Author(s):  
Li Li ◽  
Marie-Jo Halaby ◽  
Anne Hakem ◽  
Renato Cardoso ◽  
Samah El Ghamrasni ◽  
...  
Keyword(s):  
Dna Damage ◽  
Class Switch Recombination ◽  
Dependent Manner ◽  
Dna Double Strand Breaks ◽  
Dna Breaks ◽  
Class Switch ◽  
Physiological Processes ◽  
Increased Sensitivity

Signaling and repair of DNA double-strand breaks (DSBs) are critical for preventing immunodeficiency and cancer. These DNA breaks result from exogenous and endogenous DNA insults but are also programmed to occur during physiological processes such as meiosis and immunoglobulin heavy chain (IgH) class switch recombination (CSR). Recent studies reported that the E3 ligase RNF8 plays important roles in propagating DNA DSB signals and thereby facilitating the recruitment of various DNA damage response proteins, such as 53BP1 and BRCA1, to sites of damage. Using mouse models for Rnf8 mutation, we report that Rnf8 deficiency leads to impaired spermatogenesis and increased sensitivity to ionizing radiation both in vitro and in vivo. We also demonstrate the existence of alternative Rnf8-independent mechanisms that respond to irradiation and accounts for the partial recruitment of 53bp1 to sites of DNA damage in activated Rnf8−/− B cells. Remarkably, IgH CSR is impaired in a gene dose-dependent manner in Rnf8 mutant mice, revealing that these mice are immunodeficient. In addition, Rnf8−/− mice exhibit increased genomic instability and elevated risks for tumorigenesis indicating that Rnf8 is a novel tumor suppressor. These data unravel the in vivo pleiotropic effects of Rnf8.

scholarly journals Plant-Specific AtS40.4 Acts as a Negative Regulator in Abscisic Acid Signaling During Seed Germination and Seedling Growth in Arabidopsis

2021 ◽  
Vol 12 ◽  
Author(s):  
Xiao-Pu Shi ◽  
Jing-Jing Ren ◽  
Hao-Dong Qi ◽  
Yi Lin ◽  
Yu-Yi Wang ◽  
...  
Keyword(s):  
Abscisic Acid ◽  
Seed Germination ◽  
Seedling Growth ◽  
Stress Responses ◽  
Negative Regulator ◽  
Aba Signaling ◽  
Early Seedling Growth ◽  
Early Seedling ◽  
Increased Sensitivity ◽  
Aba Response

Abscisic acid (ABA) is an important phytohormone regulating plant growth, development and stress responses. A multitude of key factors implicated in ABA signaling have been identified; however, the regulation network of these factors needs for further information. AtS40.4, a plant-specific DUF584 domain-containing protein, was identified previously as a senescence regulator in Arabidopsis. In this study, our finding showed that AtS40.4 was negatively involved in ABA signaling during seed germination and early seedling growth. AtS40.4 was highly expressed in seeds and seedlings, and the expression level was promoted by ABA. AtS40.4 was localized both in the nucleus and the cytoplasm. Moreover, the subcellular localization pattern of AtS40.4 was affected by ABA. The knockdown mutants of AtS40.4 exhibited an increased sensitivity to ABA, whereas the overexpression of AtS40.4 decreased the ABA response during seed germination and seedling growth of Arabidopsis. Furthermore, AtS40.4 was involved in ABRE-dependent ABA signaling and influenced the expression levels of ABA INSENTIVE (ABI)1-5 and SnRK2.6. Further genetic evidence demonstrated that AtS40.4 functioned upstream of ABI4. These findings support the notion that AtS40.4 is a novel negative regulator of the ABA response network during seed germination and early seedling growth.

Abscisic acid controls embryo growth potential and endosperm cap weakening during coffee (Coffea arabica cv. Rubi) seed germination

Planta ◽  
2004 ◽  
Vol 220 (2) ◽  
pp. 251-261 ◽  
Author(s):  
E. A. Amaral da Silva ◽  
Peter E. Toorop ◽  
Adriaan C. van Aelst ◽  
Henk W. M. Hilhorst
Keyword(s):  
Abscisic Acid ◽  
Seed Germination ◽  
Coffea Arabica ◽  
Growth Potential

scholarly journals Epigenetic Mechanisms Are Involved in the Oncogenic Properties of ZNF518B in Colorectal Cancer

Cancers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 1433
Author(s):  
Francisco Gimeno-Valiente ◽  
Ángela L. Riffo-Campos ◽  
Luis Torres ◽  
Noelia Tarazona ◽  
Valentina Gambardella ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Chromatin Immunoprecipitation ◽  
Zinc Finger Protein ◽  
Dependent Manner ◽  
Mrna Isoforms ◽  
Histone Methyltransferases ◽  
Therapeutic Possibility ◽  
Cell Dissemination ◽  
Chip Analysis ◽  
Hct116 Cells

The ZNF518B gene, which is up-regulated in colorectal cancer, plays a role in cell dissemination and metastasis. It encodes a zinc-finger protein, which interacts with histone methyltransferases G9A and EZH2. The expression of the two major mRNA isoforms 1 (coding for the full protein) and 2 was quantified by RT-qPCR in a cohort of 66 patients. The effects of silencing ZNF518B on the transcriptome of DLD1 and HCT116 cells were analysed by Clariom-S assays and validated by RT-qPCR. The recruitment of methyltransferases and the presence of H3K27me3 were studied by chromatin immunoprecipitation (ChIP). The ratio (isoform 2)/(isoform 1) negatively correlated with the relapsing of disease. The study of the transcriptome of DLD1 and HCT116 cells revealed that many genes affected by silencing ZNF518B are related to cancer. After crossing these results with the list of genes affected by silencing the histone methyltransferases (retrieved in silico), five genes were selected. ChIP analysis revealed that the recruitment of EZH2 is ZNF518B-dependent in KAT2B, RGS4 and EFNA5; the level of H3K27me3 changes in accordance. G9A also binds RGS4 and PADI3 in a ZNF518B-dependent manner. The results highlight the importance of epigenetics in cancer and open a novel therapeutic possibility, as inhibition of histone methyltransferases may reverse the disease-linked histone marks.

scholarly journals Effects of hormonal priming on seed germination of pigeon pea under cadmium stress

2015 ◽  
Vol 87 (3) ◽  
pp. 1847-1852 ◽  
Author(s):  
LARISSA C. SNEIDERIS ◽  
MARINA A. GAVASSI ◽  
MARCELO L. CAMPOS ◽  
VICTOR D'AMICO-DAMIÃO ◽  
ROGÉRIO F. CARVALHO
Keyword(s):  
Abscisic Acid ◽  
Seed Germination ◽  
Efficient Method ◽  
Physiological Responses ◽  
Cadmium Stress ◽  
Pigeon Pea ◽  
Metal Stress ◽  
Hormonal Priming

In this work we investigated whether priming with auxin, cytokinin, gibberellin, abscisic acid and ethylene, alters the physiological responses of seeds of pigeon pea germinated under water and cadmium stress. Seeds treated with water or non-treated seeds were used as control. Although compared to non-treated seeds we found that the hormone treatments improve the germination of pigeon pea under cadmium stress, however, these treatments did not differ from water. However, we also observed a trend of tolerance to the effects of cadmium in the presence of ethylene, suggesting that the use of this hormone may be an efficient method to overcome seed germination under metal stress.

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