Optical imaging of electrical activity has been suggested as a promising approach to investigate the multineuronal representation of information processing in brain tissue. While considerable progress has been made in the development of instrumentation suitable for high-speed imaging, intrinsic or extrinsic dye-mediated optical signals are often of limited use due to their slow response dynamics, low effective sensitivity, toxicity or undefined cellular origin. Protein-based and DNA-encoded voltage sensors could overcome these limitations. Here we report the design and generation of a voltage-sensitive fluorescent protein (VSFP) consisting of a voltage sensing domain of a potassium channel and a pair of cyan and yellow emitting mutants of green fluorescent protein (GFP). In response to a change in transmembrane voltage, the voltage sensor alters the amount of fluorescence resonance energy transfer (FRET) between the pair of GFP mutants. The optical signals respond in the millisecond time-scale of fast electrical signalling and are large enough to allow monitoring of voltage changes at the single cell level.

Zinc finger nuclease (ZFN) is a powerful tool for genome editing. ZFN-encoding plasmid DNA expression systems have been recently employed for the generation of gene knockout (KO) pigs, although one major limitation of this technology is the use of potentially harmful genome-integrating plasmid DNAs. Here we describe a simple, non-integrating strategy for generating KO pigs using ZFN-encoding mRNA. The interleukin-2 receptor gamma (IL2RG) gene was knocked out in porcine fetal fibroblasts using ZFN-encoding mRNAs, and IL2RG KO pigs were subsequently generated using these KO cells through somatic cell nuclear transfer (SCNT). The resulting IL2RG KO pigs completely lacked a thymus and were deficient in T and NK cells, similar to human X-linked SCID patients. Our findings demonstrate that the combination of ZFN-encoding mRNAs and SCNT provides a simple robust method for producing KO pigs without genomic integration.

Background: Homer is a postsynaptic scaffold protein that links various synaptic signaling proteins, including the type I metabotropic glutamate receptor subunits 1α and 5, the inositol 1,4,5-trisphosphate receptor, Shank and Cdc42 small GTPase. Overexpression of Homer induces changes in dendritic spine morphology in cultured hippocampal neurons. However, the molecular basis underpinning Homer-mediated spine morphogenesis remains unclear. In this study, we aimed to elucidate the structural and functional properties of the interaction between Cupidin/Homer2 and two actin-cytoskeletal regulators, Cdc42 small GTPase and Drebrin.

1. The Na+-K+ pump current (Ip) was studied in sino-atrial (SA) node cells of rabbits using the whole-cell patch-clamp technique. 4. The cation dependence of the K+ site of the Na+-K+ pump was examined using various monovalent cations. The sequence was K+ > Rb+ > Cs+ > > > Li+.5. Ip at 0 mV also increased as [Nae]p9p was increased from 10 to 150 mm at 5-4 mm K+, with a Ko.5 value of 14 mm and a nHof 1P3 (n = 54).6. Ip at 0 mV was reduced by lowering the temperature from 37 to 25°C with 30 mm Napip and 5-4 mm K+. The temperature coefficient (Qlo) for Ip was 2-1 (n = 27). 7. With 10 mM Nat1p and 5-4 mm K+, the half-activation voltage of Ip was -52 + 16 mV and the current at this voltage was 22 5 + 3 5 pA (n = 10), indicating that Ip contributes significantly to the background outward current during the normal pacemaker potential of SA node cells. Irisawa, Brown & Giles, 1993). Recently, however, the presence of a time-independent background current has been reported and it has been shown that a Na+-dependent inward current makes a significant contribution to pacemaker depolarization (Hagiwara, Irisawa, Kasanuki & Hosoda, 1992

Phosphorylation of synaptic (RS)-

Zinc-finger nucleases (ZFNs) and transcription activator-like effector nucleases (TALENs) are new tools for producing gene knockout (KO) animals. The current study reports produced genetically modified pigs, in which two endogenous genes were knocked out. Porcine fibroblast cell lines were derived from homozygous α1,3-galactosyltransferase (GalT) KO pigs. These cells were subjected to an additional KO for the cytidine monophospho-N-acetylneuraminic acid hydroxylase (CMAH) gene. A pair of ZFN-encoding mRNAs targeting exon 8 of the CMAH gene was used to generate the heterozygous CMAH KO cells, from which cloned pigs were produced by somatic cell nuclear transfer (SCNT). One of the cloned pigs obtained was re-cloned after additional KO of the remaining CMAH allele using the same ZFN-encoding mRNAs to generate GalT/CMAH-double homozygous KO pigs. On the other hand, the use of TALEN-encoding mRNAs targeting exon 7 of the CMAH gene resulted in efficient generation of homozygous CMAH KO cells. These cells were used for SCNT to produce cloned pigs homozygous for a double GalT/CMAH KO. These results demonstrate that the combination of TALEN-encoding mRNA, in vitro selection of the nuclear donor cells and SCNT provides a robust method for generating KO pigs.

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