The properties of the inward-rectifying potassium current (IK1) were studied in the single myocytes isolated from adult mouse ventricles by the whole-cell patch-damp technique for the first time. Most of the propertie...The properties of the inward-rectifying potassium current (IK1) were studied in the single myocytes isolated from adult mouse ventricles by the whole-cell patch-damp technique for the first time. Most of the properties of IK1 including channel conductances, activation, inactivation, rectification and external K+ sensitivity in mouse ventricular myocyte were similar to those in other species, but the current-voltage (1-V) curve of mouse ventricular myocyte showed no negative slope, i.e the slope in the range of membrane potential 50 mV positive to the reversal potential (VRev) was virtually flat and remained at a low current level ((59±39) pA). Under the superfusion of Tyrode’s solution with 3mmol/L K+ and 3mmol/L Cs+, IK1 in the above region nearly decreased to zero, and then the early after-depolarization (EAD) occurred. The results suggest that this distinctive characteristic of IK1 in mouse ventricular myocyte may relate to the high susceptibility to EA0 in mouse myocardium. The inhibition of IK1展开更多
Foxj1 has been found to play an important role in cilia formation and function in vertebrates. The zebrafish or Xenopus genome expresses two Foxjl genes, foxjlalFoxJ1 and foxjlb/FoxJ1.2. In this study, we have generat...Foxj1 has been found to play an important role in cilia formation and function in vertebrates. The zebrafish or Xenopus genome expresses two Foxjl genes, foxjlalFoxJ1 and foxjlb/FoxJ1.2. In this study, we have generated a zebrafish transgenic line T2BGSZIO by Tol2 transposon-based gene trapping approach. T2BGSZ10 transgenic fish carry an insertion of the transposon genome into the first intron of thefoxj1b locus. This insertion results in GFP expression in the forebrain, otic vesicles, floorplate, pronephric ducts and other domains during embryogenesis, which recaptures the expression pattern offoxj1b. Although normal expression offoxj1b is dramatically reduced, T2BGSZ10 homozygous embryos develop normally and grow to adulthood without detectable defects, which may be due to the incomplete interruption of foxjlb expression. Nevertheless, this transgenic line may serve as a useful model for dynamic observation of GFP-labeled tissues and organs and for isolation of GFP-labeled cells.展开更多
The zebrafish sensory posterior lateral line(pLL)has become an attractive model for studying collective cell migration and cell morphogenesis.Recent studies have indicated that chemokine,Wnt/β-catenin,Fgf,and Delta-N...The zebrafish sensory posterior lateral line(pLL)has become an attractive model for studying collective cell migration and cell morphogenesis.Recent studies have indicated that chemokine,Wnt/β-catenin,Fgf,and Delta-Notch signaling pathways participate in regulating pLL development.However,it remains unclear whether TGFβsignaling pathway is involved in pLL development.Here we report a critical role of TGFβ1 in regulating morphogenesis of the pLL primordium(pLLP).The tgfβ1a gene is abundantly expressed in the lateral line primordium.Knockdown or knockout of tgfβ1a leads to a reduction of neuromast number,an increase of inter-neuromast distance,and a reduced number of hair cells.The aberrant morphogenesis in embryos depleted of tgfβ1a correlates with the reduced expression of atoh1a,deltaA,and n-cadherin/cdh2,which are known important regulators of the pLLP morphogenesis.Like tgfβ1a depletion,knockdown of smad5 that expresses in the pLLP,affects pLLP development whereas overexpression of a constitutive active Smad5 isoform rescues the defects in embryos depleted of tgfβ1a,indicating that Smad5 mediates tgfβ1a function in pLLP development.Therefore,TGFβ/Smad5 signaling plays an important role in the zebrafish lateral line formation.展开更多
文摘The properties of the inward-rectifying potassium current (IK1) were studied in the single myocytes isolated from adult mouse ventricles by the whole-cell patch-damp technique for the first time. Most of the properties of IK1 including channel conductances, activation, inactivation, rectification and external K+ sensitivity in mouse ventricular myocyte were similar to those in other species, but the current-voltage (1-V) curve of mouse ventricular myocyte showed no negative slope, i.e the slope in the range of membrane potential 50 mV positive to the reversal potential (VRev) was virtually flat and remained at a low current level ((59±39) pA). Under the superfusion of Tyrode’s solution with 3mmol/L K+ and 3mmol/L Cs+, IK1 in the above region nearly decreased to zero, and then the early after-depolarization (EAD) occurred. The results suggest that this distinctive characteristic of IK1 in mouse ventricular myocyte may relate to the high susceptibility to EA0 in mouse myocardium. The inhibition of IK1
基金supported by the National High-tech R&D Program (863 Program) (No. 2006AA02Z167)the Major Science Programs of China (No. 2006CB943401)the National Basic Research Program of China (No. 2005CB522502)
文摘Foxj1 has been found to play an important role in cilia formation and function in vertebrates. The zebrafish or Xenopus genome expresses two Foxjl genes, foxjlalFoxJ1 and foxjlb/FoxJ1.2. In this study, we have generated a zebrafish transgenic line T2BGSZIO by Tol2 transposon-based gene trapping approach. T2BGSZ10 transgenic fish carry an insertion of the transposon genome into the first intron of thefoxj1b locus. This insertion results in GFP expression in the forebrain, otic vesicles, floorplate, pronephric ducts and other domains during embryogenesis, which recaptures the expression pattern offoxj1b. Although normal expression offoxj1b is dramatically reduced, T2BGSZ10 homozygous embryos develop normally and grow to adulthood without detectable defects, which may be due to the incomplete interruption of foxjlb expression. Nevertheless, this transgenic line may serve as a useful model for dynamic observation of GFP-labeled tissues and organs and for isolation of GFP-labeled cells.
基金Acknowledgements We thank Drs Alex Schier and Susan Mango （Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA） for discussion and suggestions, Dr David Kimelman （Department of Biochemistry, University of Washington, Seattle, WA, USA） for myc-eomesa construct, and members of the Meng lab for discussion and technical assistance.
This work was financially supported by grants from the Major Science Research Programs of China （2011CB943800） and the National Natural Science Foundation of China （31221064）.
基金This work was financially supported by grants from the National Natural Science Foundation of China(#31371460)Major Science Programs of China(#2012CB945101 and#2011CB943800)。
文摘The zebrafish sensory posterior lateral line(pLL)has become an attractive model for studying collective cell migration and cell morphogenesis.Recent studies have indicated that chemokine,Wnt/β-catenin,Fgf,and Delta-Notch signaling pathways participate in regulating pLL development.However,it remains unclear whether TGFβsignaling pathway is involved in pLL development.Here we report a critical role of TGFβ1 in regulating morphogenesis of the pLL primordium(pLLP).The tgfβ1a gene is abundantly expressed in the lateral line primordium.Knockdown or knockout of tgfβ1a leads to a reduction of neuromast number,an increase of inter-neuromast distance,and a reduced number of hair cells.The aberrant morphogenesis in embryos depleted of tgfβ1a correlates with the reduced expression of atoh1a,deltaA,and n-cadherin/cdh2,which are known important regulators of the pLLP morphogenesis.Like tgfβ1a depletion,knockdown of smad5 that expresses in the pLLP,affects pLLP development whereas overexpression of a constitutive active Smad5 isoform rescues the defects in embryos depleted of tgfβ1a,indicating that Smad5 mediates tgfβ1a function in pLLP development.Therefore,TGFβ/Smad5 signaling plays an important role in the zebrafish lateral line formation.
