Thus the SNAP and FT-based methods would seem to have a variety of applications. A malfunction of regulatory degradation may result in some renal, cardiovascular, and neuronal diseases. The application of our methods in animal models will be useful to elucidate this possibility. The cDNA for mouse Kir2.1 was generously provided by Dr L.Y. Jan (Kubo et al., 1993). The cDNA for SNAP, which

is BGJ398 the mutant of the O6-alkylguanine-DNA alkyltransferase, and FT were purchased from NEB (Ipswich, MA) and Clontech (Mountain View, CA), respectively. The plasmids which express Kv1.4 and Kv2.1 were donated by Dr. Nerbonne (Washington University, St. Louis, MO). phrGFP-II, which expresses only GFP, was purchased from Stratagene (La Jolla, CA). SNAP-Kir and FT-Kir were constructed by PCR and the nucleotide sequences were checked thereafter. The SNAP-Kir2.1 gene was then cloned into pSVL (GE Healthcare, Little

Chalfont, Buckinghamshire, UK) and CSII-CMV-MCS PF-562271 molecular weight (donated from Dr. Miyoshi, Riken, Ibaraki, Japan). For the dominant-negative form of Kir2.1, the signature sequence GYG (143–145) was mutated to AAA by PCR. The E224G mutation was also introduced by PCR. The mutated SNAP-Kir2.1 genes were introduced to CSII-CMV-MCS. The plasmids were transfected into 293T cells (purchased from RIKEN BioResource Center, Ibaraki, Japan) with the calcium-phosphate method. Plasmids (3 μg) dissolved in 150 μl of 0.25 M CaCl2 was added to equal volume of 2× HBS, and the mixture was added to the 35 mm dish. The cells were washed twice with PBS 5 h after and incubated at 37 °C for up to 72 h in the presence or absence of

0.3 mM BaCl2 dissolved in the medium. The FT-Kir2.1 was expressed by pcDNA3.1 plasmid containing CMV promoter (Invitrogen, Carlsbad, CA). The lentiviral vector for SNAP-Kir2.1 was prepared as described previously (Okada and Matsuda, 2008). The Moloney retroviral vector for FT-Kir2.1 was prepared as described previously (Lin et al., 2010). Using these viral vectors, we established the 142-3 and 116-5 cell line with the limited dilution of infected 293T cells. The 293T cells were cultivated in DMEM containing 10% FBS and pencillin/streptomycin. SNAP-Kir2.1 was pulse-labeled with tuclazepam SNAP-cell-TMR-Star (2 μM) dissolved in DMEM for 45 min at 37 °C. The cells were washed twice with PBS, and further incubated in the medium for 2 h or more at 37 °C. For the confocal microscopic analysis, the 293T cells, cultivated in 35 mm dish, were fixed with 4% paraformaldehyde for 30 min at room temperature and washed with PBS. Then a coverslip was mounted with a drop of Fluoromount (Sigma, St. Louis, MO). The single plane images were taken with a confocal microscope (FV300, Olympus, Tokyo, Japan). The dichroic filter used for SNAP-Kir2.1 was rhodamine-phalloidin. Those used for FT-Kir2.1 were EGFP and Texas-red.