Ethylene response factor

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Molecular and physiological characterization of tomato (Solanum lycopersicon) ethylene response factor (ERF)

Molecular and physiological characterization of tomato (Solanum lycopersicon) ethylene response factor (ERF)

Introduction Ethylene, a gaseous plant hormone is reported to have numerous effects on developmental processes, including germination, flower and leaf senescence, fruit ripening, leaf abscission, root nodulation, programmed cell death, and responses to abiotic stresses and pathogen attacks (Johnson and Ecker, 1998; Bleecker and Kende, 2000; Pirrello et al., 2006). Components of ethylene signaling have been extensively studied in Arabidopsis (Benavente and Alonso, 2006) revealing a linear transduction pathway that leads to the activation of transcriptional regulators from the Ethylene Response Factor (ERF) type. These last components of the ethylene signaling pathway are responsible for modulating the transcription of ethylene-regulated genes. However, the apparent simplicity of the ethylene transduction pathway cannot account for the tremendous diversity of plant responses to ethylene. Because ERF proteins are encoded by one of the largest family of plant transcription factors, it is likely that diversity and specificity of ethylene responses may take place at the level of this last step of ethylene signaling. ERFs are trans-acting factors unique to plants shown to bind specifically to the GCC box cis-acting element found in the promoter regions of ethylene-responsive genes (Ohme-Takagi and Shinshi, 1995; Solano et al., 1998). The ERF family is part of the AP2/ERF superfamily which also contains the AP2 and RAV families (Riechmann. JL et al., 2000). The ERF type family is further divided into two major subfamilies, the ERF and the CBF/DREB families of transcription factors (Sakuma et al., 2002). DREB family is characterized by the presence of a valine and glutamic acid respectively at position 14 and 19 in the AP2 domain, whereas alanine and aspartic acid are conserved in the corresponding positions in the ERF proteins (Sakuma et al., 2002). In the model plant, Arabidopsis, 65 ERFs have been identified, which accounts for up to 44% of the total proteins encoding AP2/ERF domain. Structural and functional analyses performed in
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UV-C radiation modifies the ripening and accumulation of ethylene response factor (ERF) transcripts in tomato fruit

UV-C radiation modifies the ripening and accumulation of ethylene response factor (ERF) transcripts in tomato fruit

Eprints ID : 14569 To link to this article : DOI:10.1016/j.postharvbio.2015.02.001 URL : http://dx.doi.org/10.1016/j.postharvbio.2015.02.001 To cite this version : Severo, Joseana and Tiecher, Aline and Pirrello, Jullien and Regad, Farid and Latché, Alain and Pech, Jean-Claude and Bouzayen, Mondher and Rombaldi, César Valmor UV-C radiation modifies the ripening and accumulation of ethylene response factor (ERF) transcripts in tomato fruit. (2015) Postharvest Biology and Technology, vol.102. pp.9-16. ISSN 0925-5214

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Isolation and molecular characterization of ERF1, an ethylene response factor gene from durum wheat (Triticum turgidum L. subsp. durum), potentially involved in salt-stress responses

Isolation and molecular characterization of ERF1, an ethylene response factor gene from durum wheat (Triticum turgidum L. subsp. durum), potentially involved in salt-stress responses

turgidum L.  subsp. durum, or Triticum durum), also known as macaroni wheat, is the hardest of all wheat varieties and is characterized by its high protein content. To date, durum wheat is the only tetraploid wheat species of commercial importance that is widely cultivated. However, facing the rapidly growing food demand of the expanding world popu- lation, the harsh environmental conditions associated with global climate change represent a real obstacle to the increase in wheat production. In particular, salinity and drought have enormous impact on wheat and other crop yields. They exert osmotic stress and cause water deficit in plants and conse- quently affect plant growth and development ( Jin et  al., 2013 ). These impacts have driven plants to evolve various survival strategies ( Dong et al., 2012 ). Thus, it is critical to decipher the mechanisms underlying the responses of wheat to environmental stresses in order to design efficient strategies dedicated to improving stress tolerance and crop productiv- ity in these species. A common feature associated with plant adaptation to adverse environmental conditions is the regula- tion of genes involved in stress tolerance. Transcription fac- tors (TFs) are known to mediate stress signal transduction pathways regulating downstream target gene expression and lead to stress tolerance ( Shinozaki and Dennis, 2003; Chen and Zhu, 2004; Yamaguchi-Shinozaki and Shinozaki, 2005 ). Among these, the AP2/ERF TFs are specific to plants and comprise a large number of family members, reaching 163 in the Arabidopsis thaliana model plant. Ethylene response factor (ERF) and dehydration-responsive element (DRE)-binding protein (DREB)/CBF subfamilies belonging to the AP2/ERF family ( Nakano et al., 2006 ) are known to play crucial roles in plant adaptation to several environmental stresses. DREB/ CBF members are important in abiotic stress tolerance such as osmotic and cold stress ( Morran et al., 2011 ). They have been reported to recognize the DRE/C-repeat (CRT) element present in the promoter of target genes ( Stockinger et  al., 1997 ). On the other hand, ERFs bind to the GCC-box found in the promoter of ethylene-inducible and pathogen-related genes ( Ohme-Takagi and Shinshi, 1995 ), thus mediating biotic stress responses. ERFs have also been shown to be involved in abiotic stress and, for instance, TaERF3, known as a path- ogen-inducible TF ( Zhang et al., 2007 ), promotes tolerance to salt and drought stresses in hexaploid wheat (T. aestivum) ( Rong et al., 2014 ). So far, studies on AP2/ERF TFs in wheat remain scarce. In bread wheat, 117 AP2/ERF sequences have been identified, including 57 DREBs and 47 ERFs. Among the latter, only four ERF genes (TaERF1, TaERF3, TaPIEP1, and TaERF4) have been characterized and shown to be involved in abiotic stress responses ( Xu et  al., 2007; Zhang
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TdERF1, an ethylene response factor associated with dehydration responses in durum wheat (Triticum turgidum L. subsp. durum)

TdERF1, an ethylene response factor associated with dehydration responses in durum wheat (Triticum turgidum L. subsp. durum)

To cite this version : Makhloufi, Emna and Yousfi, Fatma-Ezzahra and Pirrello, Julien and Bernadac, Anne and Ghorbel, Abdelwahed and Bouzayen, Mondher TdERF1, an ethylene response factor associated with dehydration responses in durum wheat (Triticum turgidum L. subsp. durum). (2015) Plant Signaling and Behavior, vol. 10 (n° 10). pp. 1-4. ISSN 1559-2316

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Ethylene Response Factor Sl-ERF.B.3 Is Responsive to Abiotic Stresses and Mediates Salt and Cold Stress Response Regulation in Tomato

Ethylene Response Factor Sl-ERF.B.3 Is Responsive to Abiotic Stresses and Mediates Salt and Cold Stress Response Regulation in Tomato

Sl-ERF.B.3 (Solanum lycopersicum ethylene response factor B.3) gene encodes for a tomato transcription factor of the ERF (ethylene responsive factor) family. Our results of real-time RT-PCR showed that Sl-ERF.B.3 is an abiotic stress responsive gene, which is induced by cold, heat, and flooding, but downregulated by salinity and drought. To get more insight into the role of Sl-ERF.B.3 in plant response to separate salinity and cold, a comparative study between wild type and two Sl-ERF.B.3 antisense transgenic tomato lines was achieved. Compared with wild type, Sl-ERF.B.3 antisense transgenic plants exhibited a salt stress dependent growth inhibition. This inhibition was significantly enhanced in shoots but reduced in roots, leading to an increased root to shoot ratio. Furthermore, the cold stress essay clearly revealed that introducing antisense Sl-ERF.B.3 in transgenic tomato plants reduces their cell injury and enhances their tolerance against 14 d of cold stress. All these results suggest that Sl-ERF.B.3 gene is involved in plant response to abiotic stresses and may play a role in the layout of stress symptoms under cold stress and in growth regulation under salinity.
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Sl-ERF2, a Tomato Ethylene Response Factor Involved in Ethylene
Response and Seed Germination

Sl-ERF2, a Tomato Ethylene Response Factor Involved in Ethylene Response and Seed Germination

ripening- and wound-associated expression, yet its transcript accumulation was unaffected by ethylene treatment in tomato leaves (Tournier et al. 2003). ERFs have been shown to be involved in normal and abnormal plant developmental processes such as plant defense (Zhou et al. 1997, Thara et al., 1999, Brown et al. 2003, Chakravarthy et al. 2003, Cheong et al. 2003), osmotic stress tolerance (Park et al. 2001, Zhang et al. 2004) and seed germination (Finkelstein et al. 1998; Song et al. 2005). Seed germination is one of the earliest and most important steps of the plant life cycle as it allows embryos to develop into seedlings. In many plant species, germination is preceded by dormancy which is known to be maintained by ABA (Hilhorst et al. 1995) while gibberellin is required for breaking dormancy and inducing germination (Karssen et al. 1989, Debeaujon and Koorneef 2000). Germination is characterized by radicle protrusion as a result of weakening of the endosperm region enclosing the radicle tip, termed the endosperm cap (Groot and Karsen 1987). The ABA-insensitive Arabidopsis mutant abi4 affected in seed germination displays altered expression of seed-specific genes (Finkelstein et al. 1998) and the abi4 mutation is caused by a single pair deletion within an APETALA2 gene (Finkelstein et al. 1998). While it has been known for a long time that ethylene impacts seed germination, it was demonstrated only recently that ERFs are involved in ethylene-dependent regulation of seed germination (Song et al. 2005). It was reported that AtERF7 acts as a transcriptional repressor of the ABA response and that transgenic Arabidopsis lines expressing an RNAi construct targeted to down-regulate the AtERF7 gene are more sensitive to ABA and germinate later than the wild-type seeds.
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Comprehensive Profiling of Ethylene Response Factor Expression Identifies Ripening-Associated ERF Genes and Their Link to Key Regulators of Fruit Ripening in Tomato

Comprehensive Profiling of Ethylene Response Factor Expression Identifies Ripening-Associated ERF Genes and Their Link to Key Regulators of Fruit Ripening in Tomato

Although an increasing number of studies address- ing the functional significance of ERF genes are now becoming available, little is known about their position in the regulatory network triggering and orchestrating the ripening process. This study identifies a subset of ERF genes as being potentially important in controlling fruit ripening via both ethylene-dependent and RIN/ NOR-mediated mechanisms. However, the involve- ment of other phytohormones such as auxin is also likely to be important in tuning the expression of ERFs during fruit ripening. This is supported by the recent study showing that SlARF2 is an important component of the regulatory mechanism controlling tomato fruit ripening (Hao et al., 2015). Interestingly, a high number of ERFs, including SlERF.E1 and SlERF.E4, are signif- icantly down-regulated in the SlARF2 ripening- impaired mutant (Hao et al., 2015). Overall, the data designate ERFs from subclass E as priority targets for further functional characterization aiming to position these transcription factors in the gene regulatory net- works underlying fruit ripening. It is worth mentioning here that a distinctive feature of subclass E ERFs is the presence of the N-terminal MCGGAII/L motif, con- served across all plant species (Tournier et al., 2003), which was shown recently to be responsible for post- translational degradation through the N-end rule pathway under aerobic conditions (Licausi et al., 2011; Gibbs et al., 2015). Subclass E ERFs play an important role in the oxygen-sensing (hypoxic) response, and under low oxygen, they undergo relocalization into the nucleus, where they induce the transcription of their target genes (Licausi et al., 2011). Considering the marked rise in the expression of ERFs from subclass E at the onset of fruit ripening, which is associated with an increase in respiration, these ERFs might represent the missing link between the climacteric rise in respiration and autocatalytic ethylene production. In particular, it is important to further clarify whether members of this ERF subclass are involved in activating SYSTEM2 eth- ylene biosynthesis genes. The implementation of new approaches, such as in vivo ChIP coupled with high- throughput sequencing, is anticipated to yield essential information on the direct target genes of these ERFs and, hence, to provide clues concerning the control of the specific pathway(s) in which these transcriptional regulators are involved.
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The chimeric repressor version of an Ethylene Response Factor(ERF) family member, Sl-ERF.B3, shows contrasting effects on tomato fruit ripening

The chimeric repressor version of an Ethylene Response Factor(ERF) family member, Sl-ERF.B3, shows contrasting effects on tomato fruit ripening

responses via the feedback regulation of genes encoding compo- nents of ethylene signaling and other ERFs (Liu et al., 2013). Here, we show that the expression of this dominant repression version of Sl-ERF.B3 (ERF.B3-SRDX) broadly impacts tomato fruit development and ripening. The ripening-related phenotypes displayed by the ERF.B3-SRDX lines are supportive of a promi- nent role for Sl-ERF.B3 in regulating important aspects of fruit ripening in tomato, including the attainment of competence to ripen and subsequent changes in color and texture. Although Sl-ERF.B3 expression is high in stem tissue, the induced accumu- lation of its transcripts at the Br stage is indicative of an active role for this ERF gene in triggering the ripening process and, in this regard, it is not surprising that the onset of ripening is delayed in the dominant repressor lines. Compared with the wild-type, the time period from anthesis to Br was extended by c. 2 wk in the transgenic lines, indicating that the dominant repres- sion activity of Sl-ERF.B3 impacts tomato early fruit develop- ment and, particularly, the attainment of competence to ripen. Another obvious effect of Sl-ERF.B3-SRDX on fruit development is the reduced fruit size and bumpy shape, as a result of a reduc- tion in epidermal cell size and a defect in the normal coordinated expansion of the pericarp (Fig. S3). This is illustrated by a thicker pericarp, smaller volume of jelly and dry/crumbly appearance of the pericarp, suggesting a defect in the expansion or elasticity of the epidermis.
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Functional characterization of Sl-ERF.B3, a member of the large multi-gene family of Ethylene Response Factor in tomato (Solanum lycopersicum)

Functional characterization of Sl-ERF.B3, a member of the large multi-gene family of Ethylene Response Factor in tomato (Solanum lycopersicum)

More particularly, my work aimed to decipher the role of Sl-ERF.B.3, a member of ERF family gene, in mediating ethylene response and tomato plant development and fruit ripening using adv[r]

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Ethylene response factors are controlled by multiple harvesting stresses in hevea brasiliensis

Ethylene response factors are controlled by multiple harvesting stresses in hevea brasiliensis

* pascal.montoro@cirad.fr Abstract Tolerance of recurrent mechanical wounding and exogenous ethylene is a feature of the rub- ber tree. Latex harvesting involves tapping of the tree bark and ethephon is applied to increase latex flow. Ethylene is an essential element in controlling latex production. The ethylene sig- nalling pathway leads to the activation of Ethylene Response Factor (ERF) transcription fac- tors. This family has been identified in Hevea brasiliensis. This study set out to understand the regulation of ERF genes during latex harvesting in relation to abiotic stress and hormonal treat- ments. Analyses of the relative transcript abundance were carried out for 35 HbERF genes in latex, in bark from mature trees and in leaves from juvenile plants under multiple abiotic stresses. Twenty-one HbERF genes were regulated by harvesting stress in laticifers, revealing an overrepresentation of genes in group IX. Transcripts of three HbERF-IX genes from HbERF-IXc4, HbERF-IXc5 and HbERF-IXc6 were dramatically accumulated by combining wounding, methyl jasmonate and ethylene treatments. When an ethylene inhibitor was used, the transcript accumulation for these three genes was halted, showing ethylene-dependent induction. Subcellular localization and transactivation experiments confirmed that several members of HbERF-IX are activator-type transcription factors. This study suggested that latex harvesting induces mechanisms developed for the response to abiotic stress. These mechanisms probably depend on various hormonal signalling pathways. Several members of HbERF-IX could be essential integrators of complex hormonal signalling pathways in Hevea.
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Ethylene response factors are controlled by multiple harvesting stresses in hevea brasiliensis

Ethylene response factors are controlled by multiple harvesting stresses in hevea brasiliensis

* pascal.montoro@cirad.fr Abstract Tolerance of recurrent mechanical wounding and exogenous ethylene is a feature of the rub- ber tree. Latex harvesting involves tapping of the tree bark and ethephon is applied to increase latex flow. Ethylene is an essential element in controlling latex production. The ethylene sig- nalling pathway leads to the activation of Ethylene Response Factor (ERF) transcription fac- tors. This family has been identified in Hevea brasiliensis. This study set out to understand the regulation of ERF genes during latex harvesting in relation to abiotic stress and hormonal treat- ments. Analyses of the relative transcript abundance were carried out for 35 HbERF genes in latex, in bark from mature trees and in leaves from juvenile plants under multiple abiotic stresses. Twenty-one HbERF genes were regulated by harvesting stress in laticifers, revealing an overrepresentation of genes in group IX. Transcripts of three HbERF-IX genes from HbERF-IXc4, HbERF-IXc5 and HbERF-IXc6 were dramatically accumulated by combining wounding, methyl jasmonate and ethylene treatments. When an ethylene inhibitor was used, the transcript accumulation for these three genes was halted, showing ethylene-dependent induction. Subcellular localization and transactivation experiments confirmed that several members of HbERF-IX are activator-type transcription factors. This study suggested that latex harvesting induces mechanisms developed for the response to abiotic stress. These mechanisms probably depend on various hormonal signalling pathways. Several members of HbERF-IX could be essential integrators of complex hormonal signalling pathways in Hevea.
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Under-expression of the Auxin Response Factor Sl-ARF4 improves post-harvest behavior of tomato fruits

Under-expression of the Auxin Response Factor Sl-ARF4 improves post-harvest behavior of tomato fruits

1 University of Toulouse; INPT; Laboratory of Genomics and Biotechnology of Fruit; Castanet-Tolosan, France; 2 INRA; UMR990 Génomique et Biotechnologie des Fruits; Chemin de Borde Rouge; Castanet-Tolosan, France Keywords: auxin, auxin response factor, ARF4, fruit, firmness, shelf life, tomato Fruit ontogeny and ripening are genetically regulated processes involving a complex multi-hormonal control. While the role of ethylene in triggering and regulating the ripening of climacteric fruit have been clearly demonstrated, little is known about the contribution of other hormones. 1 The plant hormone Auxin plays
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Influence of colemanite on the fire retardancy of ethylene-vinyl acetate and ethylene-methyl acrylate copolymers

Influence of colemanite on the fire retardancy of ethylene-vinyl acetate and ethylene-methyl acrylate copolymers

EMA Colemanite a b s t r a c t In the present work, colemanite, a hydrated calcium borate, was used as co- filler in aluminium hydroxide/ethylene-vinyl acetate copolymers (ATH/EVA). The presence of colemanite showed an improvement of the fire properties of composites. However, this additive does not act as a synergistic agent with ATH, but seems to increase signi ficantly fire properties by his own. The formation of an expanded layer during cone calorimetry tests insulates the sample and reduces the heat release rate (HRR) values. The performance is ascribed to the hardening of the barrier layer due to the modification of colemanite structure at high temperature. Moreover, to study its mechanisms of fire retardancy and to investigate its potential synergistic effects, colemanite was also introduced as co-filler in magnesium hydroxide (MH)/EVA, ATH/ethylene-methyl acrylate (EMA) and MH/EMA composites.
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Effect of salicylic acid on the interaction between ethylene and polyamines in the short term response of tomato to salinity stress.

Effect of salicylic acid on the interaction between ethylene and polyamines in the short term response of tomato to salinity stress.

This study aimed to determine the effects of exogenous application of salicylic acid (SA) on the toxic effects of salt in relation to ethylene and polyamine (PA) synthesis, and to corre[r]

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Silencing Sl-EBF1 and Sl-EBF2 expression causes constitutive ethylene response phenotype, accelerated plant senescence, and fruit ripening in tomato

Silencing Sl-EBF1 and Sl-EBF2 expression causes constitutive ethylene response phenotype, accelerated plant senescence, and fruit ripening in tomato

Sl-EBF1 and Sl-EBF2 expression is positively regulated by ethylene and negatively regulated by auxin To determine whether Sl-EBF1 and Sl-EBF2 are under ethylene regulation, Q-PCR was used to test their relative mRNA accumulation upon short-time exogenous ethylene treatment. In light-grown seedlings, both Sl-EBF1 and Sl-EBF2 show clear responsiveness to ethylene (Fig. 4A). Sl-EBF2 mRNA levels display a dramatic increase (73-fold) in treated seedlings while, comparatively, Sl-EBF1 show only a modest increase (4-fold) in the same conditions. The regulation of tomato EBF genes in the flower during the transition from anthesis to post-anthesis prompted us to test their potential responsiveness to auxin, a key plant hormone controlling fruit set. The expression of both Sl-EBF1 and Sl-EBF2 genes was found to be negatively regulated upon exogenous treatment by IAA, the major auxin compound (Fig. 4B). However, opposite to ethylene treatment for which Sl-EBF2 was the most responsive, Table 1. Comparative analysis of Sl-EBFs amino acid sequences
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Caspase-8-dependent HER-2 cleavage in response to tumor necrosis factor alpha stimulation is counteracted by nuclear factor kappa B through c-FLIP-L expression

Caspase-8-dependent HER-2 cleavage in response to tumor necrosis factor alpha stimulation is counteracted by nuclear factor kappa B through c-FLIP-L expression

HER-2 expression inhibits cell death by inducing antiapoptotic pathways, such as Bcl-2 and Bcl-XL up-regulation (66), or by acti- vation of the Akt/NF ␬B prosurvival cascade (67–69). NF␬B is an extensively described antiapoptotic transcription factor whose nuclear DNA binding is potently and rapidly induced by TNF- ␣ in almost all of the cell lines (70). Constitutive NF ␬B activation has been observed in a wide variety of cancers and is associated with a resistance to apoptosis because many of its target genes code for antiapoptotic molecules (10 –25). In our model, TNF- ␣ stimulation leads to NF␬B activation and subsequent expression of one of its target genes,
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Apolipoprotein A-I and platelet factor 4 are biomarkers for infliximab response in rheumatoid arthritis.

Apolipoprotein A-I and platelet factor 4 are biomarkers for infliximab response in rheumatoid arthritis.

We focused initially on the 28 kDa protein that is overexpressed in the responder population and is also the first node of the decision tree, and we identified it as apolipoprotein A-I. Apolipoprotein A-I is the major protein component of HDL (High Density Protein) particles and the primary acceptor for cholesterol in extra-hepatic tissues. In RA, several studies have reported a decrease of circulating levels of apolipoprotein A-I and HDL-cholesterol in patients compared to the general population [24-26], and concentration of both parameters increases significantly in patients responding to a DMARD (Disease-Modifying Anti-Rheumatic Drug) treatment compared to non-responders.[27] On the other hand, apolipoprotein A-I was highly expressed in inflamed RA synovial tissues particularly in perivascular areas containing infiltrated T cells and macrophages, but was not detected in normal tissue [28] or in the synovium of non-inflammatory RA.[29] Moreover, increased levels of apolipoprotein A-I and cholesterol have been measured in RA synovial fluid.[30] As apolipoprotein A-I was reported to inhibit the synthesis of the major inflammatory cytokines TNF α and interleukin-1 β by blocking direct contact between T lymphocytes and monocytes [31], increased levels of this protein in synovial tissue could modulate inflammation and disease evolution by controlling interactions between immune cells and then cytokine production.[28, 32] This specific function as a “negative” acute phase protein is also emphasised in a study reporting that patients with lower levels of apolipoprotein A-1 develop more systemic inflammatory response syndrome criteria.[33]
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Differential sensitivity to ethylene of the various ripening pathways of ethylene-suppressed cantaloupe melons

Differential sensitivity to ethylene of the various ripening pathways of ethylene-suppressed cantaloupe melons

Guis, M., Latché, A., Bouzayen, M., Pech, J.C., Rose J.K., Hadfield, K.A. and Bennett, A.B., 1999. Understanding the role of ethylene in fruit softening using antisense ACC oxidase melons. In: Kanellis AK et al. (eds.) Biology and biotechnology of the plant hormone ethylene II. Kluwer Acad. Pub., Dordrecht, The Netherlands, pp. 395-396. Murray, A.J., Hobson, G.E., Schuch, W. and Bird, C.R., 1993. Reduced ethylene

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Hyd ubiquitinates the NF-κB co-factor Akirin to operate an effective immune response in Drosophila

Hyd ubiquitinates the NF-κB co-factor Akirin to operate an effective immune response in Drosophila

According to literature, Hyd is suspected to also deposit K48 polyubiquitin chains on its target proteins [ 28 ]. Here we observed that Akirin-V5 was also decorated by K48-polyubiqui- tin chains, but independently of Hyd ( S5 Fig ). Collectively, these data suggest that upon immune challenge, Hyd physically interacts with Akirin through its catalytic HECT domain to decorate Akirin with K63-polyUb chains. We previously published that Akirin physically bridges the NF-κB factor Relish and Bap60, a core member of the SWI/SNF chromatin-remodeling complex [ 19 ]. To understand whether Akirin K63-polyubiquitination is instrumental for the interaction of Akirin with Relish or Bap60, we performed co-immunoprecipitation experiments in S2 cells depleted for Hyd and transfected with Akirin-V5 and Rel68-HA or BAP60-HA ( Fig 3D ). As previously reported [ 19 ], Akirin-V5 co-precipitated either with the active form of the NF-κB homolog Relish (Rel68-HA) or with Bap60 (Bap60-HA) ( Fig 3D ). However, in the absence of Hyd, the interaction between Akirin- V5 and Rel68-HA was weakened ( Fig 3D ). Of note the interaction between Akirin-V5 and Bap60-HA is independent of Hyd ( Fig 3D ). Upon immune challenge, the transcriptional kinetic of Akirin-dependent and Akirin-independent genes was different. Akirin-independent genes ( AttD, Pgrp-LB) were strongly transcribed after 1 hour, whereas Akirin-dependent genes
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ER5, a tomato cDNA encoding an ethylene-responsive LEA-like protein:
characterization and expression in response to drought, ABA and wounding

ER5, a tomato cDNA encoding an ethylene-responsive LEA-like protein: characterization and expression in response to drought, ABA and wounding

Our data show that, as with many Lea genes [16], ER5 is induced by drought stress in both roots and leaves. Moreover, in tomato roots this drought induc- tion appears to be mediated by ethylene since the inhibitor of ethylene action, 1-MCP, efficiently pre- vents its expression during drought stress. In contrast, 1-MCP failed to eliminate the drought-induced expres- sion of ER5 in tomato leaves indicating the existence of at least two different drought response pathways. The efficiency of 1-MCP treatment in suppressing the ethylene-induced ER5 transcript accumulation is shown in Figure 1. Although it is well known that ethylene production increases in response to water deficit [1, 3, 9], its role in the response mechan- ism is not established. Here we demonstrate for the first time that drought-induced gene expression can be mediated by ethylene. However, the expression pattern obtained during drought might differ from the transi- ent induction observed upon exogenous ethylene treat- ment. Our results also show that the drought related expression of ethylene-responsive genes may involve other factors beside ethylene. Since exogenous ABA induced ER5 expression in leaves, it is possible that this hormone, whose levels increase during water stress [7], is involved in the drought induction of the ER5 gene in leaf tissues.
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