scholarly journals Arabidopsis ECERIFERUM3 (CER3) Plays a Critical Role in Maintaining Hydration for Pollen-Stigma Recognition during Fertilization

2019 ◽  
Author(s):  
Faqing Xu ◽  
Xiaojing Li ◽  
Zhongnan Yang ◽  
Sen Zhang
Keyword(s):  
Critical Role ◽  
Pollen Grains ◽  
Underlying Mechanism ◽  
Recognition System ◽  
Development Stage ◽  
Male Sterile ◽  
Foreign Pollen ◽  
Compatible Pollen ◽  
Mutant Pollen

ABSTRACTPlants distinguish the pollen grains that land on their stigmas, only allowing compatible pollen to fertilize female gametes. To analyze the underlying mechanism, conditional male-sterile mutations with affected pollen coat and disrupted pollen-stigma recognition were isolated and described. The mutant pollen failed to germinate, but germinated in vitro, suggesting that they are viable. In mutants, stigma cells that contacted their own pollen generated callose, a carbohydrate produced in response to foreign pollen. High humidity restored pollen hydration and successful fertilization, indicating defective dehydration in pollen-stigma interaction. Further analysis results from mixed pollination experiments demonstrated that the mutant pollen specifically lacked a functional pollen-stigma recognition system. The sterile plants lacked stem waxes and displayed postgenital fusion between aerial floral organs. In addition, the mutant pollen was deficient in long-chain lipids and had excess tryphine. Transmission electron microscopy observation showed that mutant pollen had almost the same surface structure as the wild type at bicellular pollen stage. However, abnormal plastoglobuli were observed in the plastids of the mutant tapetum, which was indicative of altered lipid accumulation. CER3 transcript was found in anther tapetum and microspores at development stage 9 while CER3-GFP fusion protein was localized to the cell plasma membrane. Our data reveal that CER3 is required for biosynthesis of tryphine lipids which play a critical role in maintaining hydration for pollen-stigma recognition during fertilization.

The protective effect of melatonin on the in vitro development of yak embryos against hydrogen peroxide-induced oxidative injury

Zygote ◽  
2019 ◽  
Vol 27 (3) ◽  
pp. 118-125 ◽  
Author(s):  
Wei Peng ◽  
Mengtong Lei ◽  
Jun Zhang ◽  
Yong Zhang
Keyword(s):  
Oxidative Stress ◽  
Hydrogen Peroxide ◽  
Critical Role ◽  
Underlying Mechanism ◽  
Preimplantation Embryos ◽  
Effective Antioxidant ◽  
Vitro Development ◽  
Oxidation Effect

SummaryMelatonin plays a critical role in several types of cells as an antioxidant to protect intracellular molecules from oxidative stress. The anti-oxidation effect of melatonin in yak embryos is largely unknown. We report that melatonin can protect the development of yak preimplantation embryos against oxidative stress induced by hydrogen peroxide (H2O2). Therefore, the quality of blastocysts developed from zygotes exposed to H2O2 was promoted. In addition, we observed that melatonin reduced H2O2-induced intracellular reactive oxygen species (ROS) levels and prevented mitochondrial dysfunction in zygotes. These phenomena revealed the effective antioxidant activity of melatonin to prevent oxidative stress in yak embryos. To determine the underlying mechanism, we further demonstrated that melatonin protected preimplantation embryos from oxidative damage by preserving antioxidative enzymes. Collectively, these results confirmed the anti-oxidation effect of melatonin in yak embryos that significantly improved the quantity and quality of blastocysts in the in vitro production of embryos in yaks.

scholarly journals A therapeutic dose of doxorubicin activates ubiquitin-proteasome system-mediated proteolysis by acting on both the ubiquitination apparatus and proteasome

2008 ◽  
Vol 295 (6) ◽  
pp. H2541-H2550 ◽  
Author(s):  
Jinbao Liu ◽  
Hanqiao Zheng ◽  
Mingxin Tang ◽  
Youn-Chul Ryu ◽  
Xuejun Wang
Keyword(s):  
Critical Role ◽  
Proteasome Inhibition ◽  
Ubiquitin Proteasome System ◽  
Underlying Mechanism ◽  
3T3 Cells ◽  
New Findings ◽  
Relevant Dose ◽  
Ubiquitin Proteasome ◽  
Endogenous Substrates

The ubiquitin proteasome system (UPS) degrades abnormal proteins and most unneeded normal proteins, thereby playing a critical role in protein homeostasis in the cell. Proteasome inhibition is effective in treating certain forms of cancer, while UPS dysfunction is increasingly implicated in the pathogenesis of many severe and yet common diseases. It has been previously shown that doxorubicin (Dox) enhances the degradation of a UPS surrogate substrate in mouse hearts. To address the underlying mechanism, in the present study, we report that 1) Dox not only enhances the degradation of an exogenous UPS reporter (GFPu) but also antagonizes the proteasome inhibitor-induced accumulation of endogenous substrates (e.g., β-catenin and c-Jun) of the UPS in cultured NIH 3T3 cells and cardiomyocytes; 2) Dox facilitates the in vitro degradation of GFPu and c-Jun by the reconstituted UPS via the enhancement of proteasomal function; 3) Dox at a therapeutically relevant dose directly stimulates the peptidase activities of purified 20S proteasomes; and 4) Dox increases, whereas proteasome inhibition decreases, E3 ligase COOH-terminus of heat shock protein cognate 70 in 3T3 cells via a posttranscriptional mechanism. These new findings suggest that Dox activates the UPS by acting directly on both the ubiquitination apparatus and proteasome.

scholarly journals Anatomical Characteristics of Petalized Anther Abortion in Male Sterile Camellia oleifera Plants

2021 ◽  
pp. 1-13
Author(s):  
Yang Hu ◽  
Chao Gao ◽  
Quanen Deng ◽  
Jie Qiu ◽  
Hongli Wei ◽  
...  
Keyword(s):  
Germination Rate ◽  
Pollen Grains ◽  
Relative Activity ◽  
Control Group ◽  
Camellia Oleifera ◽  
Male Sterile ◽  
Flower Bud ◽  
Triphenyltetrazolium Chloride ◽  
Pollen Sacs

Petalized anther abortion is an important characteristic of male sterility in plants. The male sterile plants (HB-21) evincing petalized anther abortion previously discovered in a clone population of the Camellia oleifera cultivar Huashuo by our research group were selected as the experimental material in this study. Using plant microscopy and anatomic methods and given the correspondence between external morphology and internal structure, we studied the anatomic characteristics of petalized anther abortion (with a fertile plant as the control group) in various stages, from flower bud differentiation to anther maturity, in hopes of providing a theoretical basis for research on and applications of male sterile C. oleifera plants, a new method for the selection of male sterile C. oleifera cultivars, and improvements in the yield and quality of C. oleifera. In this study, the development of anthers in C. oleifera was divided into 14 stages. Petalized anther abortion in male sterile plants was mainly initiated in the second stage (the stage of sporogenous cells). Either the petalized upper anther parts did not form pollen sacs, or the entire anthers did not form pollen sacs. The lower parts of some anthers could form deformed pollen sacs and develop, and these anthers could be roughly divided into two types: fully and partially petalized anthers. Abnormal callose and the premature degradation of the tapetum occurred in the pollen sacs formed by partially petalized anthers during the development process, resulting in the absence of inclusions in the pollen grains formed. Small quantities of mature pollen grains withered inward from the germinal furrows, exhibiting obvious abortion characteristics. The relative in vitro germination rate of the pollen produced by the partially petalized anthers of sterile plants was 11.20%, and the relative activity of triphenyltetrazolium chloride was 3.24%, while the fully petalized anthers did not generate pollen grains. Either the petalized anthers in male sterile plants did not produce pollen, or the vitality of the small amounts of pollen produced by sterile plants was very low compared with that of fertile plants. Such male sterile plants could be used to select correct clones and have good prospects for application in production.

ENHANCEMENT OF POLLEN GERMINATION BY PROMOTIVE FACTORS IN INCOMPATIBLE POLLEN

1999 ◽  
Vol 47 (3) ◽  
pp. 165-168
Author(s):  
Dan Eisikowitch ◽  
Hazel Y. Wetzstein
Keyword(s):  
Pollen Grains ◽  
Commercial Production ◽  
In Vitro Assays ◽  
Viable Seed ◽  
Inhibitory Effects ◽  
Incompatible Pollen ◽  
Elemental Analyses ◽  
Compatible Pollen ◽  
Selection Of

Cultivated and wild almonds are self-incompatible and thus require outcrossing by insect pollinators to produce viable seed. In commercial production, considerable efforts are directed towards placement and selection of cultivars for cross-pollination. However, since honeybees do not distinguish between the different cultivars, stigmas are usually covered by a mixture of both compatible and incompatible pollen. Using in vitro assays, we demonstrated that pollen extracts promoted germination in self pollen with no inhibitory effects observed. Elemental analyses of pollen extracts showed that enhanced levels of Ca, Mg, K, Na, and P were eluted from the grains. From this, we raise the question of possible interaction between compatible and incompatible pollen, and speculate that incompatible pollen grains may support and enhance germination of adjacent compatible pollen.

scholarly journals SYP72 interacts with the mechanosensitive channel MSL8 to protect pollen from hypoosmotic shock during hydration

2022 ◽  
Vol 13 (1) ◽  
Author(s):  
Xuemei Zhou ◽  
Yifan Zheng ◽  
Ling Wang ◽  
Haiming Li ◽  
Yingying Guo ◽  
...  
Keyword(s):  
Pollen Germination ◽  
Critical Role ◽  
Pollen Grains ◽  
Flowering Plants ◽  
Mechanosensitive Channel ◽  
Snare Protein ◽  
Pollen Hydration ◽  
Hypoosmotic Shock ◽  
Cellular Integrity ◽  
Mutant Pollen

AbstractIn flowering plants, hydration of desiccated pollen grains on stigma is a prerequisite for pollen germination, during which pollen increase markedly in volume through water uptake, requiring them to survive hypoosmotic shock to maintain cellular integrity. However, the mechanisms behind the adaptation of pollen to this hypoosmotic challenge are largely unknown. Here, we identify the Qc-SNARE protein SYP72, which is specifically expressed in male gametophytes, as a critical regulator of pollen survival upon hypoosmotic shock during hydration. SYP72 interacts with the MSCS-LIKE 8 (MSL8) and is required for its localization to the plasma membrane. Intraspecies and interspecies genetic complementation experiments reveal that SYP72 paralogs and orthologs from green algae to angiosperms display conserved molecular functions and rescue the defects of Arabidopsis syp72 mutant pollen facing hypoosmotic shock following hydration. Our findings demonstrate a critical role for SYP72 in pollen resistance to hypoosmotic shock through the MSL8 cascade during pollen hydration.

scholarly journals GATA3 interacts with and stabilizes HIF-1α to enhance cancer cell invasiveness

Oncogene ◽  
2017 ◽  
Vol 36 (30) ◽  
pp. 4243-4252 ◽  
Author(s):  
M-C Lin ◽  
J-J Lin ◽  
C-L Hsu ◽  
H-F Juan ◽  
P-J Lou ◽  
...  
Keyword(s):  
Target Genes ◽  
Critical Role ◽  
Hypoxia Inducible Factor ◽  
Disease Free Survival ◽  
Underlying Mechanism ◽  
Immunodeficient Mice ◽  
Mediated Effects ◽  
Cell Invasiveness

Abstract GATA binding protein 3 (GATA3) is indispensable in development of human organs. However, the role of GATA3 in cancers remains elusive. Hypoxia inducible factor (HIF)-1 plays an important role in pathogenesis of human cancers. Regulation of HIF-1α degradation is orchestrated through collaboration of its interacting proteins. In this study, we discover that GATA3 is upregulated in head and neck squamous cell carcinoma (HNSCC) and is an independent predictor for poor disease-free survival. GATA3 promotes invasive behaviours of HNSCC and melanoma cells in vitro and in immunodeficient mice. Mechanistically, GATA3 physically associates with HIF-1α under hypoxia to inhibit ubiquitination and proteasomal degradation of HIF-1α, which is independent of HIF-1α prolyl hydroxylation. Chromatin immunoprecipitation assays show that the GATA3/HIF-1α complex binds to and regulates HIF-1 target genes, which is also supported by the microarray analysis. Notably, the GATA3-mediated invasiveness can be significantly reversed by HIF-1α knockdown, suggesting a critical role of HIF-1α in the underlying mechanism of GATA3-mediated effects. Our findings suggest that GATA3 stabilizes HIF-1α to enhance cancer invasiveness under hypoxia and support the GATA3/HIF-1α axis as a potential therapeutic target for cancer treatment.

scholarly journals An L-type lectin receptor-like kinase promotes starch accumulation during rice pollen maturation

Development ◽  
2021 ◽  
pp. dev.196378
Author(s):  
Zhiyuan He ◽  
Ting Zou ◽  
Qiao Xiao ◽  
Guoqiang Yuan ◽  
Miaomiao Liu ◽  
...  
Keyword(s):  
Starch Synthesis ◽  
Pollen Grains ◽  
Starch Accumulation ◽  
Male Sterile ◽  
Pollen Maturation ◽  
Lectin Receptor ◽  
Rice Mutant ◽  
Receptor Like Kinase ◽  
Mutant Pollen

Starch accumulation is key for the maturity of rice pollen grains; however, the regulatory mechanism underlying this process remains unknown. Here, we isolated a male-sterile rice mutant, abnormal pollen 1 (ap1), which produces nonviable pollen grains with defective starch accumulation. Functional analysis revealed that AP1 encodes an active L-type lectin receptor-like kinase (L-LecRLK). AP1 is localized to the plasma membrane and its transcript is highly accumulated in pollen during the starch synthesis phase. RNA-seq and phosphoproteomic analysis revealed that the expression/phosphorylation levels of numerous genes/proteins involved in starch and sucrose metabolism pathway were significantly altered in the mutant pollen, including a known rice UDP-glucose pyrophosphorylase (OsUGP2). We further found that AP1 physically interacts with OsUGP2 to elevate its enzymatic activity likely through targeted phosphorylation. These findings revealed a novel role of L-LecRLK in controlling pollen maturity via modulating sucrose and starch metabolism.

scholarly journals A novel pathway of LPS uptake through syndecan-1 leading to pyroptotic cell death

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Shigetoshi Yokoyama ◽  
Yan Cai ◽  
Miyuki Murata ◽  
Takeshi Tomita ◽  
Mitsuhiro Yoneda ◽  
...  
Keyword(s):  
Cell Death ◽  
Cancer Cells ◽  
Immune Cells ◽  
Critical Role ◽  
Underlying Mechanism ◽  
Innate Immune ◽  
Cell Surface Receptor ◽  
Innate Immune Cells ◽  
Surface Receptor

Intracellular lipopolysaccharide (LPS) triggers the non-canonical inflammasome pathway, resulting in pyroptosis of innate immune cells. In addition to its well-known proinflammatory role, LPS can directly cause regression of some tumors, although the underlying mechanism has remained unknown. Here we show that secretoglobin(SCGB)3A2, a small protein predominantly secreted in airways, chaperones LPS to the cytosol through the cell surface receptor syndecan-1; this leads to pyroptotic cell death driven by caspase-11. SCGB3A2 and LPS co-treatment significantly induced pyroptosis of macrophage RAW264.7 cells and decreased cancer cell proliferation in vitro, while SCGB3A2 treatment resulted in reduced progression of xenograft tumors in mice. These data suggest a conserved function for SCGB3A2 in the innate immune system and cancer cells. These findings demonstrate a critical role for SCGB3A2 as an LPS delivery vehicle; they reveal one mechanism whereby LPS enters innate immune cells leading to pyroptosis, and they clarify the direct effect of LPS on cancer cells.

scholarly journals SRGN Promotes Colorectal Cancer Metastasis as a Critical Downstream Target of HIF-1α

2018 ◽  
Vol 48 (6) ◽  
pp. 2429-2440 ◽  
Author(s):  
Yang Xu ◽  
Jie  Xu ◽  
Yanfang Yang ◽  
Lei Zhu ◽  
Xubin Li ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Cancer Metastasis ◽  
Critical Role ◽  
Underlying Mechanism ◽  
Migration And Invasion ◽  
Potential Candidate ◽  
Metastatic Progression ◽  
Downstream Target ◽  
Underlying Mechanisms

Background/Aims: The chondroitin sulfate proteoglycan serglycin (SRGN), a hematopoietic cell granule proteoglycan, has been implicated in promoting tumor metastasis; however, the underlying mechanisms remain to be elucidated. The present study aimed to investigate the SRGN gene expression and its regulation as downstream signaling of hypoxia-inducible transcription factor 1 alpha (HIF-1α) in colorectal cancer (CRC) cells and tissues. Methods: The expression of SRGN was analyzed in CRC specimens for its correlation with progression and metastasis. Using chromatin-immunoprecipitation (ChIP), quantitative real-time PCR, Western blot, and transwell assay, the functional role and underlying mechanism of SRGN in CRC metastasis were elucidated. Thus, this study provides evidence of a critical role of SRGN in metastatic progression of CRC. Results: Our results indicated that SRGN overexpression was significantly associated with poor prognosis in CRC specimens. SRGN overexpression promoted CRC cell migration and invasion in vitro; however, SRGN depletion exhibited contrasting effects. Mechanistic investigations revealed that HIF-1α regulated SRGN transcription via physically binding to a hypoxia response element in its promoter region. Conclusions: In conclusion, we demonstrated that dysregulated HIF-1α/SRGN signaling promotes CRC progression and metastasis. SRGN may serve as a potential candidate therapeutic target for metastatic CRC.

scholarly journals Long noncoding RNA MALAT1 promotes cardiomyocyte apoptosis after myocardial infarction via targeting miR-144-3p

2019 ◽  
Vol 39 (8) ◽  
Author(s):  
Xiaohong Gong ◽  
Yun Zhu ◽  
Haixia Chang ◽  
Yongqin Li ◽  
Feng Ma
Keyword(s):  
Myocardial Infarction ◽  
Noncoding Rna ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Critical Role ◽  
Underlying Mechanism ◽  
Myocardial Apoptosis ◽  
Injury Model

AbstractOur study aims to excavate the role of metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) in myocardial infarction (MI), especially in an ischemia/reperfusion injury model and the underlying mechanism involving the MALAT1-miR144 axis. Our results demonstrated that the expression of MALAT1 has a higher level, while miR-144 expression significantly reduced in myocardial tissue after MI and also in left anterior descending (LAD)-ligation mice. This result was confirmed in vitro studies in HL-1 cardiomyocytes followed with hypoxia/reoxygenation. In addition, overexpression of MALAT1 by MALAT1-pcDNA injection into the mice with LAD increased myocardial apoptosis in vivo, while this effect was attenuated by miR-144 mimic. Bioinformatics analysis exhibits that 3′-UTR of MALAT1 is targeted to the miR-144-3p. Up-regulation miR-144 blunted the hypoxia- or MALAT1-induced cell apoptosis. In conclusion, the expression of MALAT1 was increased, whereas miR-144 expression was down-regulated in the myocardium after AMI. MALAT1 up-regulation plays a critical role in promoting cardiomyocytes apoptosis via targeting miR-144.

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