The WRKY gene family is among the largest families of transcription factors （TFs） in higher plants. By regulating the plant hormone signal transduction pathway, these TFs play critical roles in some plant processes ...The WRKY gene family is among the largest families of transcription factors （TFs） in higher plants. By regulating the plant hormone signal transduction pathway, these TFs play critical roles in some plant processes in response to biotic and abiotic stress, Various bodies of research have demonstrated the important biological functions of WRKY TFs in plant response to different kinds of biotic and abiotic stresses and working mecha- nisms. However, very li2ttle summarization has been done to review their research progress. Not iust important TFs function in plant response to biotic and abiotic stresses, WRKY also participates in carbohydrate synthesis, senes- cence, development, and secondary metabolites synthesis. WRKY proteins can bind to W-box （TGACC （A/T）） in the promoter of its target genes and activate or repress the expression of downstream genes to regulate their stress response. Moreover, WRKY proteins can interact with other TFs to regulate plant defensive responses. In the present review, we focus on the structural characteristics of WRKY TFs and the research progress on their functions in plant responses to a variety of stresses.展开更多
PURPOSE: To review the recent developments in the structure and function of Smad proteins. DATA SOURCES: Both Chinese- and English-language literatures were searched using MEDLINE/CD-ROM (1997 - 2000) and the Index of...PURPOSE: To review the recent developments in the structure and function of Smad proteins. DATA SOURCES: Both Chinese- and English-language literatures were searched using MEDLINE/CD-ROM (1997 - 2000) and the Index of Chinese-Language Literature (1997 - 2000). STUDY SELECTION: Data from published articles about TGF-beta signal transduction in recent domestic and foreign literature were selected. DATA EXTRACTION: Data were mainly extracted from 22 articles which are listed in the reference section of this review. RESULTS: Smad proteins mediate signal transduction induced by the TGF-beta superfamily. Based on their structural and functional properties, Smad proteins are divided into three groups. The first group, receptor-regulated Smads (R-Smads), are phosphorylated by activated type I receptors and form heteromeric complexes with the second group of Smads, common mediator Smads (Co-Smads). These Smad complexes translocate into the nucleus to influence gene transcription. Inhibitory Smads (I-Smads) are the third group and these antagonize the activity of R-Smads. In the nucleus, Smads can directly contact Smad-binding elements (SBE) in target gene promoters. Through interaction with different transcription factors, transcriptional co-activators or co-repressors, Smads elicit different effects in various cell types. The aberrance of Smad proteins has been noted in several human disorders such as fibrosis, hypertrophic scarring and cancer. CONCLUSION: The structure of Smads determines their function as transcriptional factors which translocate signals from the cell surface to the nucleus where Smads regulate TGF-beta superfamily-dependent gene expression.展开更多
Naive CD4 T cells can differentiate into at least two different types ofT helpers, Thl and Th2 cells. Th2 cells, capable of producing IL-4, IL-5 and IL-13, are involved in humoral immunity against extracellular pathog...Naive CD4 T cells can differentiate into at least two different types ofT helpers, Thl and Th2 cells. Th2 cells, capable of producing IL-4, IL-5 and IL-13, are involved in humoral immunity against extracellular pathogens and in the induction of asthma and other allergic diseases. In this review, we summarize recent reports regarding the transcription factors involved in Th2 differentiation and cell expansion, including StatS, Gfi- 1 and GATA-3. Stats activation is necessary and sufficient for IL-2-mediated function in Th2 differentiation. Enhanced Stats signaling induces Th2 differentiation independent of IL-4 signaling; although it does not up-regulate GATA-3 expression, it does require the presence of GATA-3 for its action. Gfi-1, induced by IL-4, promotes the expansion of GATA-3-expressing cells. Analysis of conditional Gata3 knockout mice confirmed the critical role of GATA-3 in Th2 cell differentiation （both IL-4 dependent and IL-4 independent） and in Th2 cell proliferation and also showed the importance of basal GATA-3 expression in inhibiting Thl differentiation.展开更多
CD4 T helper （Th） cells play critical roles in adaptive immune responses. They recruit and activate other immune cells including B cells, CD8 T cells, macrophages, mast cells, neutrophils, eosinophils and basophils....CD4 T helper （Th） cells play critical roles in adaptive immune responses. They recruit and activate other immune cells including B cells, CD8 T cells, macrophages, mast cells, neutrophils, eosinophils and basophils. Based on their functions, their pattern of cytokine secretion and their expression of specific transcription factors, Th cells, differentiated from naive CD4 T cells, are classified into four major lineages, Thl, Th2, Th17 and T regulatory （Treg） cells, although other Th lineages may exist. Subsets of the same lineage may express different effector cytokines, reside at different locations or give rise to cells with different fates, whereas cells from different lineages may secrete common cytokines, such as IL-2, IL-9 and IL-10, resulting in massive heterogeneity of the Th cell population. In addition, the pattern of cytokine secretion may switch from that of one lineage toward another under certain circumstances, suggesting that Th cells are plastic. Tregs are also more heterogeneous and plastic than were originally thought. In this review, we summarize recent reports on heterogeneity and plasticity of Th cells, and discuss potential mechanisms and implications of such features that Th cells display.展开更多
AIM: Critical illnesses such as sepsis, trauma, and burns cause a growth hormone insensitivity, which leads to an increased negative nitrogen balance. Endotoxin is generously released into blood under these conditions...AIM: Critical illnesses such as sepsis, trauma, and burns cause a growth hormone insensitivity, which leads to an increased negative nitrogen balance. Endotoxin is generously released into blood under these conditions and stimulates the production of proinflammatory cytokines such as TNF-alpha, IL-6, and IL-1, which may play a very important role in inducing the growth hormone insensitivity. The objective of this current study was to investigate the role of endotoxin, TNF-alpha and IL-6 in inducing the growth hormone insensitivity at the receptor and post-receptor levels. METHODS: Spague-Dawley rats were injected with endotoxin, TNF-alpha, and IL-6, respectively and part of rats injected with endotoxin was treated with exogenous somatotropin simultaneously. All rats were killed at different time points. The expression of IGF-I, GHR, SOCS-3 and beta-actin mRNA in the liver was detected by RT-PCR and the GH levels were measured by radioimmunoassay, the levels of TNF-alpha and IL-6 were detected by ELISA. RESULTS: There was no significant difference in serous GH levels between experimental group and control rats after endotoxin injection, however, liver IGF-I mRNA expression had been obviously down-regulated in endotoxemic rats. Liver GHR mRNA expression also had a predominant down-regulation after endotoxin injection. The lowest regulation of liver IGF-I mRNA expression occurred at 12h after LPS injection, being decreased by 53% compared with control rats. For GHR mRNA expression, the lowest expression occurred at 8h and had a 81% decrease. Although SOCS-3 mRNA was weakly expressed in control rats, it was strongly up-regulated after LPS injection and had a 7.84 times increase compared with control rats. Exogenous GH could enhance IGF-I mRNA expression in control rats, but it did fail to prevent the decline in IGF-I mRNA expression in endotoxemic rats. Endotoxin stimulated the production of TNF-alpha and IL-6, and the elevated IL-6 levels was shown a positive correlation with increased SOCS-3 mRNA expression. The li展开更多
基金supported by the Natural Science Foundation of China(No.31301790)Guangdong Natural Science Foundation (S2013040016220)+1 种基金China Postdoctoral Science Foundation (2013M530375,2014T70827)Shenzhen Vegetable Molecular Biotechnological Engineering Lab Scheme (Development and Reform Commission of Shenzhen Municipal Government)
文摘The WRKY gene family is among the largest families of transcription factors （TFs） in higher plants. By regulating the plant hormone signal transduction pathway, these TFs play critical roles in some plant processes in response to biotic and abiotic stress, Various bodies of research have demonstrated the important biological functions of WRKY TFs in plant response to different kinds of biotic and abiotic stresses and working mecha- nisms. However, very li2ttle summarization has been done to review their research progress. Not iust important TFs function in plant response to biotic and abiotic stresses, WRKY also participates in carbohydrate synthesis, senes- cence, development, and secondary metabolites synthesis. WRKY proteins can bind to W-box （TGACC （A/T）） in the promoter of its target genes and activate or repress the expression of downstream genes to regulate their stress response. Moreover, WRKY proteins can interact with other TFs to regulate plant defensive responses. In the present review, we focus on the structural characteristics of WRKY TFs and the research progress on their functions in plant responses to a variety of stresses.
基金supported by a grant from the National Natural Science Foundation of China(No．G1999054204)； the National Prominent Youth Science Foundation of China(No．39525024)．
文摘PURPOSE: To review the recent developments in the structure and function of Smad proteins. DATA SOURCES: Both Chinese- and English-language literatures were searched using MEDLINE/CD-ROM (1997 - 2000) and the Index of Chinese-Language Literature (1997 - 2000). STUDY SELECTION: Data from published articles about TGF-beta signal transduction in recent domestic and foreign literature were selected. DATA EXTRACTION: Data were mainly extracted from 22 articles which are listed in the reference section of this review. RESULTS: Smad proteins mediate signal transduction induced by the TGF-beta superfamily. Based on their structural and functional properties, Smad proteins are divided into three groups. The first group, receptor-regulated Smads (R-Smads), are phosphorylated by activated type I receptors and form heteromeric complexes with the second group of Smads, common mediator Smads (Co-Smads). These Smad complexes translocate into the nucleus to influence gene transcription. Inhibitory Smads (I-Smads) are the third group and these antagonize the activity of R-Smads. In the nucleus, Smads can directly contact Smad-binding elements (SBE) in target gene promoters. Through interaction with different transcription factors, transcriptional co-activators or co-repressors, Smads elicit different effects in various cell types. The aberrance of Smad proteins has been noted in several human disorders such as fibrosis, hypertrophic scarring and cancer. CONCLUSION: The structure of Smads determines their function as transcriptional factors which translocate signals from the cell surface to the nucleus where Smads regulate TGF-beta superfamily-dependent gene expression.
文摘Naive CD4 T cells can differentiate into at least two different types ofT helpers, Thl and Th2 cells. Th2 cells, capable of producing IL-4, IL-5 and IL-13, are involved in humoral immunity against extracellular pathogens and in the induction of asthma and other allergic diseases. In this review, we summarize recent reports regarding the transcription factors involved in Th2 differentiation and cell expansion, including StatS, Gfi- 1 and GATA-3. Stats activation is necessary and sufficient for IL-2-mediated function in Th2 differentiation. Enhanced Stats signaling induces Th2 differentiation independent of IL-4 signaling; although it does not up-regulate GATA-3 expression, it does require the presence of GATA-3 for its action. Gfi-1, induced by IL-4, promotes the expansion of GATA-3-expressing cells. Analysis of conditional Gata3 knockout mice confirmed the critical role of GATA-3 in Th2 cell differentiation （both IL-4 dependent and IL-4 independent） and in Th2 cell proliferation and also showed the importance of basal GATA-3 expression in inhibiting Thl differentiation.
文摘CD4 T helper （Th） cells play critical roles in adaptive immune responses. They recruit and activate other immune cells including B cells, CD8 T cells, macrophages, mast cells, neutrophils, eosinophils and basophils. Based on their functions, their pattern of cytokine secretion and their expression of specific transcription factors, Th cells, differentiated from naive CD4 T cells, are classified into four major lineages, Thl, Th2, Th17 and T regulatory （Treg） cells, although other Th lineages may exist. Subsets of the same lineage may express different effector cytokines, reside at different locations or give rise to cells with different fates, whereas cells from different lineages may secrete common cytokines, such as IL-2, IL-9 and IL-10, resulting in massive heterogeneity of the Th cell population. In addition, the pattern of cytokine secretion may switch from that of one lineage toward another under certain circumstances, suggesting that Th cells are plastic. Tregs are also more heterogeneous and plastic than were originally thought. In this review, we summarize recent reports on heterogeneity and plasticity of Th cells, and discuss potential mechanisms and implications of such features that Th cells display.
基金the key,project of the tenth-five foundation of PLA,No.01Z011
文摘AIM: Critical illnesses such as sepsis, trauma, and burns cause a growth hormone insensitivity, which leads to an increased negative nitrogen balance. Endotoxin is generously released into blood under these conditions and stimulates the production of proinflammatory cytokines such as TNF-alpha, IL-6, and IL-1, which may play a very important role in inducing the growth hormone insensitivity. The objective of this current study was to investigate the role of endotoxin, TNF-alpha and IL-6 in inducing the growth hormone insensitivity at the receptor and post-receptor levels. METHODS: Spague-Dawley rats were injected with endotoxin, TNF-alpha, and IL-6, respectively and part of rats injected with endotoxin was treated with exogenous somatotropin simultaneously. All rats were killed at different time points. The expression of IGF-I, GHR, SOCS-3 and beta-actin mRNA in the liver was detected by RT-PCR and the GH levels were measured by radioimmunoassay, the levels of TNF-alpha and IL-6 were detected by ELISA. RESULTS: There was no significant difference in serous GH levels between experimental group and control rats after endotoxin injection, however, liver IGF-I mRNA expression had been obviously down-regulated in endotoxemic rats. Liver GHR mRNA expression also had a predominant down-regulation after endotoxin injection. The lowest regulation of liver IGF-I mRNA expression occurred at 12h after LPS injection, being decreased by 53% compared with control rats. For GHR mRNA expression, the lowest expression occurred at 8h and had a 81% decrease. Although SOCS-3 mRNA was weakly expressed in control rats, it was strongly up-regulated after LPS injection and had a 7.84 times increase compared with control rats. Exogenous GH could enhance IGF-I mRNA expression in control rats, but it did fail to prevent the decline in IGF-I mRNA expression in endotoxemic rats. Endotoxin stimulated the production of TNF-alpha and IL-6, and the elevated IL-6 levels was shown a positive correlation with increased SOCS-3 mRNA expression. The li
