Microelectrophoresis of Normal and Transformed Clones of Hamster Kidney Fibroblasts

Abstract

Forrester, Macpherson and Ambrose¹ have reported some observations on the electrophoretic behaviour of two related clones of the BHK21 line of cultured hamster kidney fibroblasts, one of which had been derived from the other ‘normal’ line as a result of transformation in vitro by polyoma virus. It was found possible to distinguish the transformed clone used (C13 TC6) from the normal clone by virtue of a much increased variance in the distribution of electrophoretic mobilities in its population, coupled with a small increase in the mean value of the mobility. These observations had been made, however, on clones of cells which had passed through between 180 and 460 cell generations after the transforming event. The observed alterations in electrophoretic behaviour might, therefore, have been attributable to an accumulation of spontaneous alterations consequent on such long-term culture. Accordingly, a series of observations has been made on ‘young’ transformed clones as soon as possible after transformation. The clones were grown to about 10⁷ cells, then stored at −70°. Cells from these frozen stocks were examined after less than 8 days further growth, that is, before the 35th mean generation.