Table 1.

Activation of GFPΔRaf-1:ER induces cell cycle arrest

Cells	Days	4-HT (nm)	G1 (%)	G2/M (%)	S (%)
Babe	2	0	41.0	13.9	45.1
	2	100	42.0	12.9	45.1
	4	0	33.8	8.4	57.9
	4	100	33.5	8.4	58.0
GFPΔRaf-1[YY]:ER	2	0	51.4	14.5	34.1
	2	100	57.9	19.1	23.0
	4	0	34.8	11.9	53.3
	4	100	69.4	25.3	5.4
GFPΔRaf-1[DD]:ER	2	0	54.4	13.9	31.6
	2	100	62.6	25.7	11.6
	4	0	35.0	10.4	54.6
	4	100	67.8	30.2	2.0

Puromycin-resistant IMR-90 cells infected with control (Babe) and GFPΔRaf-1:ER-encoding retroviruses were treated with 100 nm 4-HT for 2 or 4 days and labeled with 15 μm BrdU for 3 hr. Ethanol-fixed cells were stained with FITC-anti-BrdU and with propidium iodide, and the percentage of cells in the different phases of the cell cycle was assessed by flow cytometry.