Table 2.

Cooperation between Ras effector loop mutants and cyclins in inducing anchorage-independent growth of NIH 3T3 cells

Cell line	Colony-forming efficiency (% ± SD)^a
Cell line	+pBabePuro	+Cyclin D1	+Cyclin E	+Cyclin A
neo	0	0	0	0
12V	2.2 ± 0.1	12.1 ± 1.0	4.7 ± 0.5	5.1 ± 0.6
12V,35S	0^b	1.0 ± 0.1	0.4 ± 0.1	2.0 ± 0.2
12V,37G	0^b	2.5 ± 0.1	1.2 ± 0.1	1.7 ± 0.4
12V,40C	0^b	1.7 ± 0.2	0^b	3.7 ± 0.3

↵a A total of 10,000 cells were seeded into 0.3% agar. Macroscopic colonies were scored after 2 weeks of growth. Each infection with cyclin-expressing viruses was performed twice; each pool of infectants was then analyzed twice in duplicate. Values represent averages of all determinations ± 1 standard deviation. See text for further details. +pBabePuro, cells infected with a retroviral vector lacking a cDNA insert; +cyclin D1, E, or A, cells infected with a retroviral vector that drives expression of a human cyclin of the indicated type.
↵b Formation of microscopic colonies (see footnote b to Table 1).