A mosquito strain of Aedes albopictus, HAmAal^G0, from Huntsville, Alabama, USA, showed a normal susceptibility and low tolerance to permethrin and resmethrin （pyrethroid insecticides） compared to a susceptible Ikak...A mosquito strain of Aedes albopictus, HAmAal^G0, from Huntsville, Alabama, USA, showed a normal susceptibility and low tolerance to permethrin and resmethrin （pyrethroid insecticides） compared to a susceptible Ikaken strain, even though these pyrethroid insecticides have been used in the field for a long period of time in Alabama. Recently, we treated HAmAal^G0 in the laboratory with permethrin for five generations and detected no significant change in the level of resistance to permethrin in the selected mosquitoes, HAmAal^G0, compared with the parental strain HAmAal^G0. We then examined the allelic expression at the L-to-F kdr site of the sodium channel gene in the Aedes mosquitoes to address our hypothesis that the L-to-F kdr mutation was not present in HAmAal^G0 and HAmAal^G5 mosquitoes. We found that every tested individual in Ikaken, HAmAal^G5, and HAmAal^G5 populations expressed a codon of CTA at the L-to-F kdr site encoding Leu, strongly corresponding to their susceptibility to insecticides.展开更多
The epithelial Na+ channel(ENa C) consists of α,β,γsubunits.Its expression and function are regulated by aldosterone at multiple levels including transcription.ENa C plays a key role in Na+ homeostasis and blood pr...The epithelial Na+ channel(ENa C) consists of α,β,γsubunits.Its expression and function are regulated by aldosterone at multiple levels including transcription.ENa C plays a key role in Na+ homeostasis and blood pressure.Mutations in ENa C subunit genes result in hypertension or hypotension,depending on the nature of the mutations.Transcription of αENa C is considered as the rate-limiting step in the formation of functional ENa C.As an aldosterone target gene,αENa C is activated upon aldosterone-mineralocorticoid receptor binding to the cis-elements in the αENa C promoter,which is packed into chromatin.However,how aldosterone alters chromatin structure to induce changes in transcription is poorly understood.Studies by others and us suggest that Dot1a-Af9 complex represses αENa C by directly binding and regulating targeted histone H3 K79 hypermethylation at the specific subregions of αENa C promoter.Aldosterone decreases Dot1a-Af9 formation by impairing expression of Dot1 a and Af9 and by inducing Sgk1,which,in turn,phosphorylates Af9 at S435 to weaken Dot1a-Af9 interaction.MR attenuates Dot1aAf9 effect by competing with Dot1 a for binding Af9.Af17 relieves repression by interfering with Dot1a-Af9 interaction and promoting Dot1 a nuclear export.Af17-/-mice exhibit defects in ENa C expression,renal Na+ retention,and blood pressure control.This review gives a brief summary of these novel findings.展开更多
Loss of function and gain of function mutations of the sodium channel were investigated using an intact two-dimensional rabbit sinoatrial node (SAN) and atrial cell model. The effects of three external stimuli (acetyl...Loss of function and gain of function mutations of the sodium channel were investigated using an intact two-dimensional rabbit sinoatrial node (SAN) and atrial cell model. The effects of three external stimuli (acetylcholine secretion by the vagal nerve, acid-base concentration, and tissue temperature) on cardiac pacemaker function and conduction were studied. Our results show that these two groups of mutations have different effects on pacemaker function and conduction. Furthermore, we found that the negative effects of these mutations could be altered by external stimuli. The bradycardic effects of mutations were magnified by an increase in acetylcholine level. Changes in acid-base concentration and tissue temperature increased the ability of the SAN to recover its pacemaker function. The results of this study increase our understanding of sodium channel disorders, and help to advance research on the treatment of these conditions.展开更多
Dravet syndrome is a rare epileptic encephalopathy characterized by frequent seizures beginning in the first year of life and behavioral disorders. Mutations in the sodium channel α1 subunit gene are the main cause o...Dravet syndrome is a rare epileptic encephalopathy characterized by frequent seizures beginning in the first year of life and behavioral disorders. Mutations in the sodium channel α1 subunit gene are the main cause of this disease. We report two patients with refractory seizures and psychomotor retardation in whom the final diagnosis was Dravet syndrome with confirmed mutations in the sodium channel α1 subunit gene. The mutation identified in the second patient was a novel frame shift mutation, which resulted from the deletion of five nucleotides in exon 24.展开更多
目的构建表型重叠家系相关基因SCN5A del QKP1507-1509突变型真核表达载体,研究其在H9C2细胞中的表达。方法一步法定点诱变技术构建SCN5A基因del QKP1507-1509突变型真核表达载体,电穿孔方法将野生型和突变型质粒转染至H9C2细胞,应用实...目的构建表型重叠家系相关基因SCN5A del QKP1507-1509突变型真核表达载体,研究其在H9C2细胞中的表达。方法一步法定点诱变技术构建SCN5A基因del QKP1507-1509突变型真核表达载体,电穿孔方法将野生型和突变型质粒转染至H9C2细胞,应用实时荧光定量聚合酶链反应(RFQ-PCR)及Western blot技术检测其mRNA及蛋白表达情况。结果琼脂糖凝胶电泳法及DNA直接测序法均表明定点突变成功,RFQ-PCR及Western blot结果显示,野生组、突变组和混合组SCN5A基因mRNA相对表达量分别为1.089±0.459、1.011±0.840和1.069±0.492,3组SCN5A基因mRNA相对表达量比较差异无统计学意义(P>0.05)。野生组、突变组和混合组SCN5A蛋白在H9C2细胞的相对表达量分别为3.781±0.221、3.466±0.176和3.714±0.198,3组SCN5A蛋白相对表达量比较差异无统计学意义(P>0.05)。结论成功构建钠通道基因del QKP1507-1509突变型真核表达载体并转染至H9C2细胞,该突变未引起钠通道在细胞膜的异常表达,为进一步功能研究提供了研究基础及方向。展开更多
文摘A mosquito strain of Aedes albopictus, HAmAal^G0, from Huntsville, Alabama, USA, showed a normal susceptibility and low tolerance to permethrin and resmethrin （pyrethroid insecticides） compared to a susceptible Ikaken strain, even though these pyrethroid insecticides have been used in the field for a long period of time in Alabama. Recently, we treated HAmAal^G0 in the laboratory with permethrin for five generations and detected no significant change in the level of resistance to permethrin in the selected mosquitoes, HAmAal^G0, compared with the parental strain HAmAal^G0. We then examined the allelic expression at the L-to-F kdr site of the sodium channel gene in the Aedes mosquitoes to address our hypothesis that the L-to-F kdr mutation was not present in HAmAal^G0 and HAmAal^G5 mosquitoes. We found that every tested individual in Ikaken, HAmAal^G5, and HAmAal^G5 populations expressed a codon of CTA at the L-to-F kdr site encoding Leu, strongly corresponding to their susceptibility to insecticides.
基金Supported by National Institutes of Health Grant 2R01 DK080236 06A1
文摘The epithelial Na+ channel(ENa C) consists of α,β,γsubunits.Its expression and function are regulated by aldosterone at multiple levels including transcription.ENa C plays a key role in Na+ homeostasis and blood pressure.Mutations in ENa C subunit genes result in hypertension or hypotension,depending on the nature of the mutations.Transcription of αENa C is considered as the rate-limiting step in the formation of functional ENa C.As an aldosterone target gene,αENa C is activated upon aldosterone-mineralocorticoid receptor binding to the cis-elements in the αENa C promoter,which is packed into chromatin.However,how aldosterone alters chromatin structure to induce changes in transcription is poorly understood.Studies by others and us suggest that Dot1a-Af9 complex represses αENa C by directly binding and regulating targeted histone H3 K79 hypermethylation at the specific subregions of αENa C promoter.Aldosterone decreases Dot1a-Af9 formation by impairing expression of Dot1 a and Af9 and by inducing Sgk1,which,in turn,phosphorylates Af9 at S435 to weaken Dot1a-Af9 interaction.MR attenuates Dot1aAf9 effect by competing with Dot1 a for binding Af9.Af17 relieves repression by interfering with Dot1a-Af9 interaction and promoting Dot1 a nuclear export.Af17-/-mice exhibit defects in ENa C expression,renal Na+ retention,and blood pressure control.This review gives a brief summary of these novel findings.
基金supported by the National Natural Science Foundation for Theoretical Physics of China (11047017)the Wellcome Trust (081808/Z/06/Z)+1 种基金the Biotechnology and Biological Sciences Research Council (BBS/B1678X), UKthe Special Foundation of Education of Anhui Province for Excellent Young Scientists (2011SQRL023)
文摘Loss of function and gain of function mutations of the sodium channel were investigated using an intact two-dimensional rabbit sinoatrial node (SAN) and atrial cell model. The effects of three external stimuli (acetylcholine secretion by the vagal nerve, acid-base concentration, and tissue temperature) on cardiac pacemaker function and conduction were studied. Our results show that these two groups of mutations have different effects on pacemaker function and conduction. Furthermore, we found that the negative effects of these mutations could be altered by external stimuli. The bradycardic effects of mutations were magnified by an increase in acetylcholine level. Changes in acid-base concentration and tissue temperature increased the ability of the SAN to recover its pacemaker function. The results of this study increase our understanding of sodium channel disorders, and help to advance research on the treatment of these conditions.
文摘Dravet syndrome is a rare epileptic encephalopathy characterized by frequent seizures beginning in the first year of life and behavioral disorders. Mutations in the sodium channel α1 subunit gene are the main cause of this disease. We report two patients with refractory seizures and psychomotor retardation in whom the final diagnosis was Dravet syndrome with confirmed mutations in the sodium channel α1 subunit gene. The mutation identified in the second patient was a novel frame shift mutation, which resulted from the deletion of five nucleotides in exon 24.
