Temperature-dependent properties of cells transformed by a thermosensitive mutant of polyoma virus.

In cells transformed by ts-3, a thermosensitive mutant of polyoma virus, the loss of inhibition of DNA synthesis by topographical factors (topo-inhibition), is rendered temperature-dependent, providing evidence that the viral genome controls this essential aspect of transformation. The expression of two other attributes of transformed cells, growth in agar and serum requirement for initiation of DNA synthesis in a wound in culture, is not made temperature-dependent. In productive infection of BALB-3T3 cells by ts-3, virus-induced stimulation of cellular DNA synthesis and movement is rendered temperature-dependent.