Figure 1.

Expression of VJT-6 is regulated by v-Jun. (A) v-Jun-transformed CEF overexpress VJT-6. Two micrograms of poly(A)⁺ RNA from CEF infected with the RCAS(A) vector or RCAS(A)v-Jun was analyzed by Northern blot and autoradiographed. (B) Induction of VJT-6 by the estrogen-regulated Jun-estrogen receptor chimera ΔVJ-hER. Twenty micrograms of total RNA from CEF expressing the hormone-binding domain of the human estrogen receptor (hER), v-Jun (VJ1), or ΔVJ-hER was used for Northern blots. −, Control treatment (10 μl of EtOH) for 48 hr; +, exposure to 2 μM estrogen in EtOH for 48 hr; and +/−, 48 hr of estrogen treatment, followed by 48 hr without estrogen. (C) Time course of VJT-6 induction by ΔVJ-hER. CEF infected with ΔVJ-hER were treated with estrogen for various time periods. Twenty micrograms of total RNA from each indicated time point was analyzed by Northern blot. For A–C, blots were probed with ³²P-labeled VJT-6 cDNA. Molecular markers are on the left (×1,000). Control blots for glyceraldehyde-3-phosphate dehydrogenase (GAPDH) show equal loading of the lanes. B and C were generated with different exposure times; quantitative aspects of VJT-6 induction are not comparable between B and C.