Temperature‐dependent transmembrane potential changes in cells infected with a temperature‐sensitive moloney sarcoma virus

Abstract

Normal rat kidney cells (NRK) infected with the temperature-sensitive (ts) transformation mutant of Moloney murine sarcoma virus yielded a clone of cells, 6m2, that exhibited a transformed morphology at 33 degrees C and a normal morphology at 39 degrees C. Transmembrane potential (Em) was measured fluorometrically using a cyanine dye diS-C3-(5). Fluorescence was inversely correlated with Em. Cells at 33 degrees C had lower Em. Em changes were recorded within 15 minutes of temperature shift from 33 degrees C to 39 degrees C in both directions, increasing in the 33 degrees C to 39 degrees C direction and decreasing in the 39 degrees C to 33 degrees C direction. Uninfected NRK cells when shifted under the same condition exhibited small fluorescence changes in the 33 degrees C to 39 degrees C direction. Shifting from 39 degrees C to 33 degrees C resulted in Em changes similar to those in 6m2 cells. Also studied was a cell line infected with a spontaneous revertant of the ts mutant, designated 54-5A4; it was transformed at both temperatures. Shifting from 33 degrees C to 39 degrees C in both directions yielded small changes. Transmembrane potential changes in 6m2 cells precede other transformation-specific changes that occur after a temperature shift.

Decreased hepatocyte membrane potential differences and GABAa-β3 expression in human hepatocellular carcinoma

“…1,[18][19][20][21] In each case, tumor PDs were significantly depolarized (breast, 18%; cervix, 33%; brain, 54%; stomach, 34%). Thus, our finding of a 24% decrease in HCC tissue PD is not only consistent with these reports but also reports describing depolarization in various rat and human malignant cell lines.…”

Potassium‐induced reverse transformation of cells infected with a temperature‐sensitive transformation mutant virus

“…However, the synthesis ratio of virus-specified transforming protein to marker viral protein was not altered. Na+K+-ATPase might play a role in this reversetransformation process.We recently identified very rapid transmembrane potential (Em) alterations, measured by the potential-sensitive fluorescent dye diS-Cs-6) in a clone of normal rat kidney cells (NRK) infected with a temperature-sensitive mutant Moloney sarcoma virus (ts 110); (Lai et al, 1984). These cells (6m2), isolated and described by Blair et al (1979), exhibit transformed phenotype at a permissive temperature of 33°C ( Fig.…”

Alterations in electrophoretic mobility, diaphorase activity, and terminal differentiation induced in murine erythroleukemia lines by differentiating agents

“…The bioelectrical properties of the plasma membranes of mammalian cells have frequently been observed to change when cells undergo neoplastic transformation; it has been suggested that such altered activities may be related to the genesis and maintenance of the malignant state (Bingelli and Cameron, 1980;Boonstra et al, 1981;Cone, 1974;Lai et al, 1984;Price et al, 1987). A strong correlation was found between transmembrane potential (TMP) and commitment to division in cells of 56 different origins (Binggeli and Weinstein, 19861, and cell surface charge has been found to parallel the state of transformation in some cell types.…”