FIG. 3.
EBV infection upregulates the expression of HER2 and HER3. (A) HER2 and HER3 mRNA expression levels in parental (MCF7 and BT474), EBV-infected (MCF7-A and BT474-A), and Neor (MCF7-Neor and BT474-Neor) cell lines were determined by RT-PCR. S26 was detected as an internal control. Signal changes relative to the parental control are shown. (B) Protein expression of HER1, HER2, HER3, and HER4 was detected in immunoblotting with specific antibodies. α-Tubulin was detected as an internal control. Increases in protein expression (n-fold) relative to the parental control are shown. (C) After being washed in phosphate-buffered saline, MCF7, MCF7-A, and MCF7-Neor cells were harvested in lysis buffer, and 500 μg of each lysate was immunoprecipitated with a HER2 antibody. The immune complexes were divided into equal parts for detecting HER2, HER3, p-Tyr, and p85 with specific antibodies in immunoblotting. α-Tubulin detected from 10% of cell lysates used for immunoprecipitation served as an internal control.