环核苷酸门控离子通道(Cyclic nucleotide-gated ion channels,CNGC)是非选择性的阳离子通道,受细胞内信使小分子环核苷酸(cAMP和cGMP)以及Ca^(2+)/CaM调控。哺乳动物CNGC功能的变构调节机制受到CaM结合影响,哺乳动物CNGC在胞质N和/或C...环核苷酸门控离子通道(Cyclic nucleotide-gated ion channels,CNGC)是非选择性的阳离子通道,受细胞内信使小分子环核苷酸(cAMP和cGMP)以及Ca^(2+)/CaM调控。哺乳动物CNGC功能的变构调节机制受到CaM结合影响,哺乳动物CNGC在胞质N和/或C末端具有CaMBD。在植物方面,研究大多集中于与植物CNGC的环核苷酸结合结构域重叠的C端CaM结合结构域(CaMBD)。然而近期对模式植物拟南芥CNGC12的研究提供了单个植物CNGC同种型具有多个CaMBD的证据。重点总结了动植物钙调蛋白多个结合位点调控环核苷酸门控离子通道的研究进展。展开更多
AIM： To assess the role of hyperpolarization-activated cyclic nucleotide-gated cation （HCN） channels in regu- lating the excitability of vagal and spinal gut afferents. METHODS： The mechanosensory response of mese...AIM： To assess the role of hyperpolarization-activated cyclic nucleotide-gated cation （HCN） channels in regu- lating the excitability of vagal and spinal gut afferents. METHODS： The mechanosensory response of mesen- teric afferent activity was measured in an ex vivo murine jejunum preparation. HCN channel activity was recorded through voltage and current clamp in acutely dissoci- ated dorsal root ganglia （DRG） and nodose ganglia （NG） neurons retrogradely labeled from the small intestine through injection of a fluorescent marker （DiI）. The isoforms of HCN channels expressed in DRG and NG neurons were examined by immunohistochemistry. RESULTS： Ramp distension of the small intestine evok- ed biphasic increases in the afferent nerve activity, re- flecting the activation of low- and high-threshold fibers.HCN blocker CsCl （5 mmol/L） preferentially inhibited the responses of low-threshold fibers to distension and showed no significant effects on the high-threshold re- sponses. The effect of CsCI was mimicked by the more selective HCN blocker ZD7288 （10 ~mol/L）. In 71.4% of DiI labeled DRG neurons （/7 = 20） and 90.9% of DiI labeled NG neurons （n = 10）, an inward current （Ih current） was evoked by hyperpolarization pulses which was fully eliminated by extracellular CsCI. In neurons expressing Ih current, a typical ＂sag＂ was observed upon injection of hyperpolarizing current pulses in cur- rent-clamp recordings. CsCI abolished the sag entirely. In some DiI labeled DRG neurons, the Ih current was potentiated by 8-Br-cAMP, which had no effect on the Ih current of DiI labeled NG neurons. Immunohistochem- istry revealed differential expression of HCN isoforms in vagal and spinal afferents, and HCN2 and HCN3 seemed to be the dominant isoform in DRG and NG, respec- tively.CONCLUSION： HCNs differentially regulate the excit- ability of vagal and spinal afferent of murine small in- testine.展开更多
RNA editing is a type of post-transcriptional modification that includes nucleotide insertion/deletion or conversion. Different categories of RNA editing have been widely observed in distinct RNAs from divergent organ...RNA editing is a type of post-transcriptional modification that includes nucleotide insertion/deletion or conversion. Different categories of RNA editing have been widely observed in distinct RNAs from divergent organisms. In flowering plants, RNA editing usually alters cytidine to uridine in plastids and mitochondria, playing important roles in various plant developmental processes, including organelle biogenesis, adaptation to environmental changes, and signal transduction. Numerous studies have demonstrated that a number of factors are involved in plant RNA editing, such as pentatricopeptide repeat(PPR) proteins, multiple organelle RNA editing factors(MORF, also known as RIP), organelle RNA recognition motif(ORRM) containing proteins,protoporphyrinogen IX oxidase 1(PPO1) and organelle zinc finger 1(OZ1). These factors play diverse roles in plant RNA editing due to their distinct characteristics. In this review, we discuss the functional roles of the individual editing factors and their associations in plant RNA editing.展开更多
文摘环核苷酸门控离子通道(Cyclic nucleotide-gated ion channels,CNGC)是非选择性的阳离子通道,受细胞内信使小分子环核苷酸(cAMP和cGMP)以及Ca^(2+)/CaM调控。哺乳动物CNGC功能的变构调节机制受到CaM结合影响,哺乳动物CNGC在胞质N和/或C末端具有CaMBD。在植物方面,研究大多集中于与植物CNGC的环核苷酸结合结构域重叠的C端CaM结合结构域(CaMBD)。然而近期对模式植物拟南芥CNGC12的研究提供了单个植物CNGC同种型具有多个CaMBD的证据。重点总结了动植物钙调蛋白多个结合位点调控环核苷酸门控离子通道的研究进展。
基金Supported by Science and Technology Commission of Shanghai Municipality,No. 10ZR1417300Educational Commission of Shanghai Municipality,No. 10ZZ69
文摘AIM： To assess the role of hyperpolarization-activated cyclic nucleotide-gated cation （HCN） channels in regu- lating the excitability of vagal and spinal gut afferents. METHODS： The mechanosensory response of mesen- teric afferent activity was measured in an ex vivo murine jejunum preparation. HCN channel activity was recorded through voltage and current clamp in acutely dissoci- ated dorsal root ganglia （DRG） and nodose ganglia （NG） neurons retrogradely labeled from the small intestine through injection of a fluorescent marker （DiI）. The isoforms of HCN channels expressed in DRG and NG neurons were examined by immunohistochemistry. RESULTS： Ramp distension of the small intestine evok- ed biphasic increases in the afferent nerve activity, re- flecting the activation of low- and high-threshold fibers.HCN blocker CsCl （5 mmol/L） preferentially inhibited the responses of low-threshold fibers to distension and showed no significant effects on the high-threshold re- sponses. The effect of CsCI was mimicked by the more selective HCN blocker ZD7288 （10 ~mol/L）. In 71.4% of DiI labeled DRG neurons （/7 = 20） and 90.9% of DiI labeled NG neurons （n = 10）, an inward current （Ih current） was evoked by hyperpolarization pulses which was fully eliminated by extracellular CsCI. In neurons expressing Ih current, a typical ＂sag＂ was observed upon injection of hyperpolarizing current pulses in cur- rent-clamp recordings. CsCI abolished the sag entirely. In some DiI labeled DRG neurons, the Ih current was potentiated by 8-Br-cAMP, which had no effect on the Ih current of DiI labeled NG neurons. Immunohistochem- istry revealed differential expression of HCN isoforms in vagal and spinal afferents, and HCN2 and HCN3 seemed to be the dominant isoform in DRG and NG, respec- tively.CONCLUSION： HCNs differentially regulate the excit- ability of vagal and spinal afferent of murine small in- testine.
基金supported by the Ministry of Science and Technology (2015CB910900)the Fok Ying-Tong Education Foundation (151021)+2 种基金the Fundamental Research Funds for the Central Universities (2017PY031 to Ping Yin)China Postdoctoral Science Foundation (2015M572163, 2017T100561)National Natural Science Foundation of China (31700203 to Junjie Yan)
文摘RNA editing is a type of post-transcriptional modification that includes nucleotide insertion/deletion or conversion. Different categories of RNA editing have been widely observed in distinct RNAs from divergent organisms. In flowering plants, RNA editing usually alters cytidine to uridine in plastids and mitochondria, playing important roles in various plant developmental processes, including organelle biogenesis, adaptation to environmental changes, and signal transduction. Numerous studies have demonstrated that a number of factors are involved in plant RNA editing, such as pentatricopeptide repeat(PPR) proteins, multiple organelle RNA editing factors(MORF, also known as RIP), organelle RNA recognition motif(ORRM) containing proteins,protoporphyrinogen IX oxidase 1(PPO1) and organelle zinc finger 1(OZ1). These factors play diverse roles in plant RNA editing due to their distinct characteristics. In this review, we discuss the functional roles of the individual editing factors and their associations in plant RNA editing.
