In recent decades,the potential health hazards of microwave exposure have been attracting increasing attention.Our previous studies have demonstrated that microwave exposure impaired learning and memory in experimenta...In recent decades,the potential health hazards of microwave exposure have been attracting increasing attention.Our previous studies have demonstrated that microwave exposure impaired learning and memory in experimental animal models[1,2].展开更多
The effects of vitamin D on osteoblast mineralization are well documented. Reports of the effects of vitamin D on osteoclasts, however, are conflicting, showing both inhibition and stimulation. Finding that resorbing ...The effects of vitamin D on osteoblast mineralization are well documented. Reports of the effects of vitamin D on osteoclasts, however, are conflicting, showing both inhibition and stimulation. Finding that resorbing osteoclasts in human bone express vitamin D receptor (VDR), we examined their response to different concentrations of 25-hydroxy vitamin D3 [25(OH)D3] (100 or 500 nmol·L^-1) and 1,25-dihydroxy vitamin D3 [1,25(OH)2D3] (0.1 or 0.5 nmol·L^-1) metabolites in cell cultures. Specifically, CD14+ monocytes were cultured in charcoal-stripped serum in the presence of receptor activator of nuclear factor kappa-B ligand (RANKL) and macrophage colony-stimulating factor (M-CSF). Tartrate-resistant acid phosphatase (TRAP) histochemical staining assays and dentine resorption analysis were used to identify the size and number of osteoclast cells, number of nuclei per cell and resorption activity. The expression of VDR was detected in human bone tissue (ex vivo) by immunohistochemistry and in vitro cell cultures by western blotting. Quantitative reverse transcription-PCR (qRT-PCR) was used to determine the level of expression of vitamin D-related genes in response to vitamin D metabolites. VDR-related genes during osteoclastogenesis, shown by qRT-PCR, was stimulated in response to 500 nmol·L^-1 of 25(OH)D3 and 0.1-0.5 nmol·L^-1 of 1,25(OH)2D3, upregulating cytochrome P450 family 27 subfamily B member I (CYP27B1) and cytochrome P450 family 24 subfamily A member I (CYP24A1). Osteoclast fusion transcripts transmembrane 7 subfamily member 4 (tm7sf4) and nuclear factor of activated T-cell cytoplasmic 1 (nfatcl) where downregulated in response to vitamin D metabolites. Osteoclast number and resorption activity were also increased. Both 25(OH)D3 and 1,25(OH)2D3 reduced osteoclast size and number when co-treated with RANKL and M-CSF. The evidence for VDR expression in resorbing osteoclasts in vivo and low-dose effects of 1,25(OH)2D3 on osteoclasts in vitro may therefore provide insight into the effects of clinical vitamin D treatments, further providing a counterpoint to the high-dose effects reported from in vitro experiments.展开更多
BMP2 plays crucial roles in vertebrate developmental process and acts as a bone inducer during osteogenesis. We present here the molecular cloning of bmp2 cDNA from the marine flatfish Cynoglossus semilaevis, and the ...BMP2 plays crucial roles in vertebrate developmental process and acts as a bone inducer during osteogenesis. We present here the molecular cloning of bmp2 cDNA from the marine flatfish Cynoglossus semilaevis, and the analysis of bmp2 expression profiling and promoter function. The full length of bmp2 cDNA sequence is 2 048 bp,which encodes a protein of 422 amino acids. Tissue expression distribution of bmp2 was examined in 14 tissues of mature individuals by quantitative real time PCR(qRT-PCR). The results revealed that bmp2 was expressed ubiquitously, and the highest expression level was detected in the spinal cord. Moreover, bmp2 expression levels were detected at 15 sampling time points of early developmental stages(egg, larva, juvenile and fingerling stages).The highest expression level of bmp2 was observed at the gastrula stage, which was about ten times higher than those at the other three embryo stages. Whole-mount in situ hybridization showed that the bmp2 signal was strongly detected at the location of the crown-like larval fin, heart and liver, and slightly expressed in the notochord at one day post hatch(dph); then the expression of bmp2 started to be concentrated in notochord at three dph. Subsequently, we characterized the 5′-flanking region of bmp2 by testing the promoter activity by Luciferase reporter assays. Positive regulatory region was detected at the location of –179 to +109. The predicted transcription factor binding sites(E-box binding factors, zinc finger transcription factor, etc.) in this region might participate in the transcriptional regulation of the bmp2 gene.展开更多
Objective To determine the correlation of human leukocyte antigen - G ( HLA - G) expression with CMV active infection after kidney transplantation. Methods A total of 215 first - time kidney transplantation recipients...Objective To determine the correlation of human leukocyte antigen - G ( HLA - G) expression with CMV active infection after kidney transplantation. Methods A total of 215 first - time kidney transplantation recipients in one transplantation center were divided into CMV ( + ) group and CMV ( - ) group according to展开更多
BACKGROUND Sepsis is a major medical challenge.Magnolol is an active constituent of Houpu that improves tissue function and exerts strong anti-endotoxin and anti-inflammatory effects,but the mechanism by which it redu...BACKGROUND Sepsis is a major medical challenge.Magnolol is an active constituent of Houpu that improves tissue function and exerts strong anti-endotoxin and anti-inflammatory effects,but the mechanism by which it reduces intestinal inflammation in sepsis is yet unclear.AIM To assess the protective effect of magnolol on intestinal mucosal epithelial cells in sepsis and elucidate the underlying mechanisms.METHODS Enzyme-linked immunosorbent assay was used to measure tumor necrosis factor-α(TNF-α),interleukin-1β(IL-1β),IL-6,and regulated on activation,normal T-cell expressed and secreted(RANTES)levels in serum and ileal tissue in animal studies.The histopathological changes of the ileal mucosa in different groups were observed under a microscope.Cell Counting Kit-8 and cell permeability assays were used to determine the concentration of drug-containing serum that did not affect the activity of Caco2 cells but inhibited lipopolysaccharide(LPS)-induced decrease in permeability.Immunofluorescence and Western blot assays were used to detect the levels of RANTES,inhibitor of nuclear factor kappa-B kinaseβ(IKKβ),phosphorylated IKKβ(p-IKKβ),inhibitor of nuclear factor kappa-B kinaseα(IκBα),p65,and p-p65 proteins in different groups in vitro.RESULTS In rats treated with LPS by intravenous tail injection in the presence or absence of magnolol,magnolol inhibited the expression of proinflammatory cytokines,IL-1β,IL-6,and TNF-αin a dose-dependent manner.In addition,magnolol suppressed the production of RANTES in LPS-stimulated sepsis rats.Moreover,in vitro studies suggested that magnolol inhibited the increase of p65 nucleation,thereby markedly downregulating the production of the phosphorylated form of IKKβin LPS-treated Caco2 cells.Specifically,magnolol inhibited the translocation of the transcription factor nuclear factor-kappa B(NF-κB)from the cytosol into the nucleus and down-regulated the expression level of the chemokine RANTES in LPS-stimulated Caco2 cells.CONCLUSION Magnolol down-regulates RANTES levels by inhibiting the LPS/NF-κB signaling pathways,thereby suppressing IL-1β,IL-6,and TNF-αexpression to alleviate the mucosal barrier dysfunction in sepsis.展开更多
This study examined the role of regulated upon activation normal T cell expressed and secreted(RANTES) and its receptor C-C chemokine receptor type 5(CCR5) in gastric cancer metastasis and the associated mechanism...This study examined the role of regulated upon activation normal T cell expressed and secreted(RANTES) and its receptor C-C chemokine receptor type 5(CCR5) in gastric cancer metastasis and the associated mechanism.The expression of RANTES and CCR5 was detected by using immunohistochemical staining and Western blotting in the gastric cancer tissues obtained from 60 gastric cancer patients with or without lymph node metastasis(n=30 in each).The results showed that the expression levels of RANTES and CCR5 were higher in gastric cancer with lymph node metastasis than in that without metastasis(P0.05).The expression levels of RANTES in 30 lymph nodes with cancerous invasion were higher than in 30 normal lymph nodes(P0.05).Chemotactic test revealed that the number of migrating gastric cancer cells(n=295.0±54.6) induced by the protein of cancer-invading lymph nodes was greater than that by the protein mixture from cancer-invading lymph nodes and RANTES antibody(n=42.5±11.6)(P0.05).RT-PCR showed that the expression levels of the main Th1 cytokines(IL-2,γ-IFN) were lower in gastric cancer with lymph node metastasis(2.22±0.90,3.26±1.15 respectively) than in that without metastasis(3.07±1.67,4.77±1.52 respectively)(P0.05),but the expression level of the main Th 2 cytokine(IL-10) was higher in gastric cancer with lymph nodes metastasis(6.06±2.04) than in that without metastasis(4.88±1.87)(P0.05).It was concluded that RANTES and its receptor CCR5 may contribute to gastric cancer metastasis through influencing the balance of Th1/Th2.RANTES and CCR5 may become a marker of gastric cancer metastasis.展开更多
Dear Editor,Human papillomaviruses(HPV)are a large group(>200genotypes)of small double-stranded DNA viruses(https://pave.niaid.nih.gov/).Although infections by most HPV types are asymptomatic,persistent infections ...Dear Editor,Human papillomaviruses(HPV)are a large group(>200genotypes)of small double-stranded DNA viruses(https://pave.niaid.nih.gov/).Although infections by most HPV types are asymptomatic,persistent infections in cervical and ano-genital epithelia by high-risk展开更多
To test the antigenic activity of M protein (Mc protein) in the inner membrane of SARS-CoV, SARS-CoV Me protein's bases locating inside the membrane were cloned, the His-fusion protein was expressed in E. coli and ...To test the antigenic activity of M protein (Mc protein) in the inner membrane of SARS-CoV, SARS-CoV Me protein's bases locating inside the membrane were cloned, the His-fusion protein was expressed in E. coli and analyzed for its antigenic activity. Among those 7 clinically diagnosed patients' sera, there were 5 positive and 2 negative in reaction with His-fusion protein. All of the 20 healthy persons' sera and rabbit anti-OC43 and 229E were of negative reaction with His-fusion protein. The animals immunized with His-fusion protein have produced muhi-clonal antibody. The His-fusion protein could specially react with clinically diagnosed SARS patients' sera and the animals immunized with His-fusion protein could produce specifically multi-clonal antibody, but it could not react with the sera of healthy persons and the rabbit anti-OC43 and 229E.展开更多
Plant b-1,3-glucanases are members of the pathogenesis-related protein 2(PR-2) family,which is one of the 17 PR protein families and plays important roles in biotic and abiotic stress responses.One of the differenti...Plant b-1,3-glucanases are members of the pathogenesis-related protein 2(PR-2) family,which is one of the 17 PR protein families and plays important roles in biotic and abiotic stress responses.One of the differentially expressed proteins(spot 842) identified in a recent proteomic comparison between five pairs of closely related maize(Zea mays L.) lines differing in aflatoxin resistance was further investigated in the present study.Here,the corresponding cDNA was cloned from maize and designated as ZmGns.ZmGns encodes a protein of338 amino acids containing a potential signal peptide.The expression of Zm Gns was detectible in all tissues studied with the highest level in silks.ZmGns was significantly induced by biotic stresses including three bacteria and the fungus Aspergillus flavus.ZmGns was also induced by most abiotic stresses tested and growth hormones including salicylic acid.In vivo,ZmGns showed a significant inhibitory activity against thebacterial pathogen Pseudomonas syringae pv.tomato DC3000 and fungal pathogen Botrytis cinerea when it overexpressed in Arabidopsis.Its high level of expression in the silk tissue and its induced expression by phytohormone treatment,as well as by bacterial and fungal infections,suggest it plays a complex role in maize growth,development,and defense.展开更多
Auxin and cytokinin direct cell proliferation and differentiation during the in vitro culture of plant cells, but the molecular basis of these processes, especially de novo shoot regeneration, has not been fully eluci...Auxin and cytokinin direct cell proliferation and differentiation during the in vitro culture of plant cells, but the molecular basis of these processes, especially de novo shoot regeneration, has not been fully elucidated. Here, we describe the regulatory control of shoot regeneration in Arabidopsis thaliana(L.) Heynh, based on the interaction of ARABIDOPSIS RESPONSE REGULATOR12(ARR12) and WUSCHEL(WUS). The major site of ARR12 expression coincided with the location where the shoot apical meristem(SAM) initiated. The oar12 mutants showed severely impaired shoot regeneration and reduced responsiveness to cytokinin; consistent with this, the overexpression of ARR12 enhanced shoot regeneration.Certain shoot meristem specification genes, notably WUSCHEL(WUS) and CLAVATA3, were significantly downregulated in the arr1z explants. Chromatin immunoprecipitation(ChIP) and transient activation assays demonstrated that ARR12 binds to the promoter of WUS. These observations indicate that during shoot regeneration, in vitro, ARR12 functions as a molecular link between cytokinin signaling and the expression of shoot meristem specification genes.展开更多
Transposons are effective mutagens alternative to T-DNA for the generation of insertional mutants in many plant species including those whose transformation is inefficient. The current strategies of transposon tagging...Transposons are effective mutagens alternative to T-DNA for the generation of insertional mutants in many plant species including those whose transformation is inefficient. The current strategies of transposon tagging are usually slow and labor-intensive and yield low frequency of tagged lines. We have constructed a series of transposon tagging vectors based on three approaches: (i) AcTPase controlled by glucocorticoid binding domain/VP16 acidic activation domain/Gal4 DNA-binding domain (GVG) chemical-inducible expression system; (ii) deletion of AcTPase via Cre-lox site-specific recombination that was initially triggered by Ds excision; and (iii) suppression of early transposition events in transformed rice callus through a dual-functional hygromycin resistance gene in a novel Ds element (HPT-Ds), We tested these vectors in transgenic rice and characterized the transposition events. Our results showed that these vectors are useful resources for functional genomics of rice and other crop plants. The vectors are freely available for the community,展开更多
基金supported by National Science Foundation of China[No.81172620]。
文摘In recent decades,the potential health hazards of microwave exposure have been attracting increasing attention.Our previous studies have demonstrated that microwave exposure impaired learning and memory in experimental animal models[1,2].
基金financial support from Orthopaedic Research UK (P 470)Arthritis Research UK (grant 20299 and Oxford EOTC)
文摘The effects of vitamin D on osteoblast mineralization are well documented. Reports of the effects of vitamin D on osteoclasts, however, are conflicting, showing both inhibition and stimulation. Finding that resorbing osteoclasts in human bone express vitamin D receptor (VDR), we examined their response to different concentrations of 25-hydroxy vitamin D3 [25(OH)D3] (100 or 500 nmol·L^-1) and 1,25-dihydroxy vitamin D3 [1,25(OH)2D3] (0.1 or 0.5 nmol·L^-1) metabolites in cell cultures. Specifically, CD14+ monocytes were cultured in charcoal-stripped serum in the presence of receptor activator of nuclear factor kappa-B ligand (RANKL) and macrophage colony-stimulating factor (M-CSF). Tartrate-resistant acid phosphatase (TRAP) histochemical staining assays and dentine resorption analysis were used to identify the size and number of osteoclast cells, number of nuclei per cell and resorption activity. The expression of VDR was detected in human bone tissue (ex vivo) by immunohistochemistry and in vitro cell cultures by western blotting. Quantitative reverse transcription-PCR (qRT-PCR) was used to determine the level of expression of vitamin D-related genes in response to vitamin D metabolites. VDR-related genes during osteoclastogenesis, shown by qRT-PCR, was stimulated in response to 500 nmol·L^-1 of 25(OH)D3 and 0.1-0.5 nmol·L^-1 of 1,25(OH)2D3, upregulating cytochrome P450 family 27 subfamily B member I (CYP27B1) and cytochrome P450 family 24 subfamily A member I (CYP24A1). Osteoclast fusion transcripts transmembrane 7 subfamily member 4 (tm7sf4) and nuclear factor of activated T-cell cytoplasmic 1 (nfatcl) where downregulated in response to vitamin D metabolites. Osteoclast number and resorption activity were also increased. Both 25(OH)D3 and 1,25(OH)2D3 reduced osteoclast size and number when co-treated with RANKL and M-CSF. The evidence for VDR expression in resorbing osteoclasts in vivo and low-dose effects of 1,25(OH)2D3 on osteoclasts in vitro may therefore provide insight into the effects of clinical vitamin D treatments, further providing a counterpoint to the high-dose effects reported from in vitro experiments.
基金The Special Scientific Research Funds for Central Non-profit Institutes,Chinese Academy of Fishery Sciences under contract No.2016RC-LX02the National Natural Science Foundation of China under contract No.31201981
文摘BMP2 plays crucial roles in vertebrate developmental process and acts as a bone inducer during osteogenesis. We present here the molecular cloning of bmp2 cDNA from the marine flatfish Cynoglossus semilaevis, and the analysis of bmp2 expression profiling and promoter function. The full length of bmp2 cDNA sequence is 2 048 bp,which encodes a protein of 422 amino acids. Tissue expression distribution of bmp2 was examined in 14 tissues of mature individuals by quantitative real time PCR(qRT-PCR). The results revealed that bmp2 was expressed ubiquitously, and the highest expression level was detected in the spinal cord. Moreover, bmp2 expression levels were detected at 15 sampling time points of early developmental stages(egg, larva, juvenile and fingerling stages).The highest expression level of bmp2 was observed at the gastrula stage, which was about ten times higher than those at the other three embryo stages. Whole-mount in situ hybridization showed that the bmp2 signal was strongly detected at the location of the crown-like larval fin, heart and liver, and slightly expressed in the notochord at one day post hatch(dph); then the expression of bmp2 started to be concentrated in notochord at three dph. Subsequently, we characterized the 5′-flanking region of bmp2 by testing the promoter activity by Luciferase reporter assays. Positive regulatory region was detected at the location of –179 to +109. The predicted transcription factor binding sites(E-box binding factors, zinc finger transcription factor, etc.) in this region might participate in the transcriptional regulation of the bmp2 gene.
文摘Objective To determine the correlation of human leukocyte antigen - G ( HLA - G) expression with CMV active infection after kidney transplantation. Methods A total of 215 first - time kidney transplantation recipients in one transplantation center were divided into CMV ( + ) group and CMV ( - ) group according to
基金Basic Public Welfare Research Foundation of Zhejiang Province,China,No.GD21H290001and Traditional Chinese Medicine Science and Technology Project Foundation of Zhejiang Province,China,No.2020ZB072.
文摘BACKGROUND Sepsis is a major medical challenge.Magnolol is an active constituent of Houpu that improves tissue function and exerts strong anti-endotoxin and anti-inflammatory effects,but the mechanism by which it reduces intestinal inflammation in sepsis is yet unclear.AIM To assess the protective effect of magnolol on intestinal mucosal epithelial cells in sepsis and elucidate the underlying mechanisms.METHODS Enzyme-linked immunosorbent assay was used to measure tumor necrosis factor-α(TNF-α),interleukin-1β(IL-1β),IL-6,and regulated on activation,normal T-cell expressed and secreted(RANTES)levels in serum and ileal tissue in animal studies.The histopathological changes of the ileal mucosa in different groups were observed under a microscope.Cell Counting Kit-8 and cell permeability assays were used to determine the concentration of drug-containing serum that did not affect the activity of Caco2 cells but inhibited lipopolysaccharide(LPS)-induced decrease in permeability.Immunofluorescence and Western blot assays were used to detect the levels of RANTES,inhibitor of nuclear factor kappa-B kinaseβ(IKKβ),phosphorylated IKKβ(p-IKKβ),inhibitor of nuclear factor kappa-B kinaseα(IκBα),p65,and p-p65 proteins in different groups in vitro.RESULTS In rats treated with LPS by intravenous tail injection in the presence or absence of magnolol,magnolol inhibited the expression of proinflammatory cytokines,IL-1β,IL-6,and TNF-αin a dose-dependent manner.In addition,magnolol suppressed the production of RANTES in LPS-stimulated sepsis rats.Moreover,in vitro studies suggested that magnolol inhibited the increase of p65 nucleation,thereby markedly downregulating the production of the phosphorylated form of IKKβin LPS-treated Caco2 cells.Specifically,magnolol inhibited the translocation of the transcription factor nuclear factor-kappa B(NF-κB)from the cytosol into the nucleus and down-regulated the expression level of the chemokine RANTES in LPS-stimulated Caco2 cells.CONCLUSION Magnolol down-regulates RANTES levels by inhibiting the LPS/NF-κB signaling pathways,thereby suppressing IL-1β,IL-6,and TNF-αexpression to alleviate the mucosal barrier dysfunction in sepsis.
基金supported by a grant from Natural Sciences Foundation of Hubei Province of China (No. 2006ABA098)
文摘This study examined the role of regulated upon activation normal T cell expressed and secreted(RANTES) and its receptor C-C chemokine receptor type 5(CCR5) in gastric cancer metastasis and the associated mechanism.The expression of RANTES and CCR5 was detected by using immunohistochemical staining and Western blotting in the gastric cancer tissues obtained from 60 gastric cancer patients with or without lymph node metastasis(n=30 in each).The results showed that the expression levels of RANTES and CCR5 were higher in gastric cancer with lymph node metastasis than in that without metastasis(P0.05).The expression levels of RANTES in 30 lymph nodes with cancerous invasion were higher than in 30 normal lymph nodes(P0.05).Chemotactic test revealed that the number of migrating gastric cancer cells(n=295.0±54.6) induced by the protein of cancer-invading lymph nodes was greater than that by the protein mixture from cancer-invading lymph nodes and RANTES antibody(n=42.5±11.6)(P0.05).RT-PCR showed that the expression levels of the main Th1 cytokines(IL-2,γ-IFN) were lower in gastric cancer with lymph node metastasis(2.22±0.90,3.26±1.15 respectively) than in that without metastasis(3.07±1.67,4.77±1.52 respectively)(P0.05),but the expression level of the main Th 2 cytokine(IL-10) was higher in gastric cancer with lymph nodes metastasis(6.06±2.04) than in that without metastasis(4.88±1.87)(P0.05).It was concluded that RANTES and its receptor CCR5 may contribute to gastric cancer metastasis through influencing the balance of Th1/Th2.RANTES and CCR5 may become a marker of gastric cancer metastasis.
基金supported by the Intramural Research Program of the National Institutes of HealthNational Cancer Institutethe Center for Cancer Research
文摘Dear Editor,Human papillomaviruses(HPV)are a large group(>200genotypes)of small double-stranded DNA viruses(https://pave.niaid.nih.gov/).Although infections by most HPV types are asymptomatic,persistent infections in cervical and ano-genital epithelia by high-risk
文摘To test the antigenic activity of M protein (Mc protein) in the inner membrane of SARS-CoV, SARS-CoV Me protein's bases locating inside the membrane were cloned, the His-fusion protein was expressed in E. coli and analyzed for its antigenic activity. Among those 7 clinically diagnosed patients' sera, there were 5 positive and 2 negative in reaction with His-fusion protein. All of the 20 healthy persons' sera and rabbit anti-OC43 and 229E were of negative reaction with His-fusion protein. The animals immunized with His-fusion protein have produced muhi-clonal antibody. The His-fusion protein could specially react with clinically diagnosed SARS patients' sera and the animals immunized with His-fusion protein could produce specifically multi-clonal antibody, but it could not react with the sera of healthy persons and the rabbit anti-OC43 and 229E.
基金supported by USDA cooperative agreement 58-6435-6-055
文摘Plant b-1,3-glucanases are members of the pathogenesis-related protein 2(PR-2) family,which is one of the 17 PR protein families and plays important roles in biotic and abiotic stress responses.One of the differentially expressed proteins(spot 842) identified in a recent proteomic comparison between five pairs of closely related maize(Zea mays L.) lines differing in aflatoxin resistance was further investigated in the present study.Here,the corresponding cDNA was cloned from maize and designated as ZmGns.ZmGns encodes a protein of338 amino acids containing a potential signal peptide.The expression of Zm Gns was detectible in all tissues studied with the highest level in silks.ZmGns was significantly induced by biotic stresses including three bacteria and the fungus Aspergillus flavus.ZmGns was also induced by most abiotic stresses tested and growth hormones including salicylic acid.In vivo,ZmGns showed a significant inhibitory activity against thebacterial pathogen Pseudomonas syringae pv.tomato DC3000 and fungal pathogen Botrytis cinerea when it overexpressed in Arabidopsis.Its high level of expression in the silk tissue and its induced expression by phytohormone treatment,as well as by bacterial and fungal infections,suggest it plays a complex role in maize growth,development,and defense.
基金financially supported by the National Special Science Research Program of China (grant no.2013CB967300)the National High Technology Research and Development Program "863”(grant no.2013AA102602-4)+2 种基金the National Key Research and Development Program of China (grant no.2016YFD0101902)National Transgenic Project of China (Grant No.2016ZX08010002-002)the National Natural Science Foundation (grant nos.31471515,31500232,31270328,30970243)
文摘Auxin and cytokinin direct cell proliferation and differentiation during the in vitro culture of plant cells, but the molecular basis of these processes, especially de novo shoot regeneration, has not been fully elucidated. Here, we describe the regulatory control of shoot regeneration in Arabidopsis thaliana(L.) Heynh, based on the interaction of ARABIDOPSIS RESPONSE REGULATOR12(ARR12) and WUSCHEL(WUS). The major site of ARR12 expression coincided with the location where the shoot apical meristem(SAM) initiated. The oar12 mutants showed severely impaired shoot regeneration and reduced responsiveness to cytokinin; consistent with this, the overexpression of ARR12 enhanced shoot regeneration.Certain shoot meristem specification genes, notably WUSCHEL(WUS) and CLAVATA3, were significantly downregulated in the arr1z explants. Chromatin immunoprecipitation(ChIP) and transient activation assays demonstrated that ARR12 binds to the promoter of WUS. These observations indicate that during shoot regeneration, in vitro, ARR12 functions as a molecular link between cytokinin signaling and the expression of shoot meristem specification genes.
文摘Transposons are effective mutagens alternative to T-DNA for the generation of insertional mutants in many plant species including those whose transformation is inefficient. The current strategies of transposon tagging are usually slow and labor-intensive and yield low frequency of tagged lines. We have constructed a series of transposon tagging vectors based on three approaches: (i) AcTPase controlled by glucocorticoid binding domain/VP16 acidic activation domain/Gal4 DNA-binding domain (GVG) chemical-inducible expression system; (ii) deletion of AcTPase via Cre-lox site-specific recombination that was initially triggered by Ds excision; and (iii) suppression of early transposition events in transformed rice callus through a dual-functional hygromycin resistance gene in a novel Ds element (HPT-Ds), We tested these vectors in transgenic rice and characterized the transposition events. Our results showed that these vectors are useful resources for functional genomics of rice and other crop plants. The vectors are freely available for the community,