排序方式: 共有52条查询结果,搜索用时 15 毫秒
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Heightened nociceptor function caused by inflammatory mediators such as bradykinin (BK) contributes to increased pain sensitivity (hyperalgesia) to noxious mechanical and thermal stimuli. Although it is known that sensitization of the heat transducer TRPV1 largely subserves thermal hyperalgesia, the cellular mechanisms underlying mechanical hyperalgesia have been elusive. The role of the mechanically activated (MA) channel piezo2 (known as FAM38B) present in mammalian sensory neurons is unknown. We test the hypothesis that piezo2 activity is enhanced by BK, an algogenic peptide that induces mechanical hyperalgesia within minutes. Piezo2 current amplitude is increased and inactivation is slowed by bradykinin receptor beta 2 (BDKRB2) activation in heterologous expression systems. Protein kinase A (PKA) and protein kinase C (PKC) agonists enhance piezo2 activity. BDKRB2-mediated effects are abolished by PKA and PKC inhibitors. Finally, piezo2-dependent MA currents in a class of native sensory neurons are enhanced 8-fold by BK via PKA and PKC. Thus, piezo2 sensitization may contribute to PKA- and PKC-mediated mechanical hyperalgesia. 相似文献
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Molecular and genetic analysis of nitrite reductase co-suppression in transgenic tobacco plants 总被引:8,自引:0,他引:8
Hervé Vaucheret Jean-Cristophe Palauqui Taline Elmayan Barbara Moffatt 《Molecular & general genetics : MGG》1995,248(3):311-317
Silencing ofNia host genes and transgenes (encoding nitrate reductase) was previously achieved by introducing into tobacco plants the tobaccoNia2 cDNA cloned downstream of the cauliflower mosaic virus (CaMV) 35S promoter. To check whetherNii host genes and transgenes (encoding nitrite reductase, the second enzyme of the nitrate assimilation pathway) were also susceptible to silencing, a transgene consisting of the tobaccoNii1 gene with two copies of the enhancer of the 35S promoter cloned 1 kb upstream of theNii promoter region was introduced into tobacco plants. Among nine independent transformants analysed, two showed silencing ofNii host genes and transgenes in some descendants after selfing, but never after back-crossing with wild-type plants, suggesting that silencing depends on the number of transgene loci and/or on certain allelic or ectopic combinations of transgene loci. In one transformant carrying a single transgene locus in a homozygous state, silencing was triggered in all progeny plants of each generation, 20 to 50 days after germination. Field trial analysis confirmed that silencing was not triggered when the transgene locus of this latter line was present in a hemizygous state. In addition, it was revealed that silencing can be triggered, albeit at low frequency and later during the development, when this transgene locus is brought into the presence of a non-allelic transgene locus by crossing, suggesting that a homozygous state is not absolutely required. 相似文献
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A TRP channel that senses cold stimuli and menthol 总被引:48,自引:0,他引:48
Peier AM Moqrich A Hergarden AC Reeve AJ Andersson DA Story GM Earley TJ Dragoni I McIntyre P Bevan S Patapoutian A 《Cell》2002,108(5):705-715
A distinct subset of sensory neurons are thought to directly sense changes in thermal energy through their termini in the skin. Very little is known about the molecules that mediate thermoreception by these neurons. Vanilloid Receptor 1 (VR1), a member of the TRP family of channels, is activated by noxious heat. Here we describe the cloning and characterization of TRPM8, a distant relative of VR1. TRPM8 is specifically expressed in a subset of pain- and temperature-sensing neurons. Cells overexpressing the TRPM8 channel can be activated by cold temperatures and by a cooling agent, menthol. Our identification of a cold-sensing TRP channel in a distinct subpopulation of sensory neurons implicates an expanded role for this family of ion channels in somatic sensory detection. 相似文献
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To examine whether molecular similarities exist between the animal and plant Rho GTPase signaling pathways, we have developed a heterologous two-hybrid screening method. By this technique, we have cloned a cDNA encoding a tobacco Rac-like protein able to interact with a mammalian Rho-GDI. In a second screen this tobacco Rac was used as a bait and a tobacco homologue of Rho-GDI was identified. These results show that some components of the animal and plant Rac signaling pathways are similar enough to allow their interaction in an heterologous approach. Moreover these data suggest a similar regulation of Rho GTPases in animals and plants. 相似文献
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Jean‐Sébastien Parent Nathalie Bouteiller Taline Elmayan Hervé Vaucheret 《The Plant journal : for cell and molecular biology》2015,81(2):223-232
Dicer proteins are central to the different mechanisms involving RNA interference. Plants have evolved multiple DICER‐LIKE (DCL) copies, thus enabling functional diversification. In Arabidopsis, DCL2 and DCL4 process double‐stranded RNA into 22 and 21 nucleotide small interfering (si)RNAs, respectively, and have overlapping functions with regards to virus and transgene silencing. Nonetheless, some studies have reported that dcl2 or dcl4 single mutations are sometimes sufficient to hinder silencing. To better dissect the role of DCL2 and DCL4, we analyzed silencing kinetics and efficiencies using different transgenic systems in single and double mutant backgrounds. The results indicate that DCL2 stimulates transitivity and secondary siRNA production through DCL4 while being sufficient for silencing on its own. Notably, silencing of 35S‐driven transgenes functions more efficiently in dcl4 mutants, indicating that DCL4 mostly obscures DCL2 in wild‐type plants. Nonetheless, in a dcl4 mutant compromised in phloem‐originating silencing, ectopically expressed DCL2 allows restoration of silencing, suggesting that DCL2 is not, or poorly, expressed in phloem. Remarkably, this ectopic DCL2 contribution to phloem‐originating silencing is dependent on the activity of RNA‐DEPENDENT RNA POLYMERASE6. These results indicate that, despite differences in the silencing activity of their small RNA products, DCL2 and DCL4 mostly act redundantly yet hierarchically when present simultaneously. 相似文献