Relationship between LMP1 expression and levels of nuclear CREB in BCL cells. (A) Parent and LMP1-expressing clones of the M12.4.1 BCL cell line were stained with fluorescent anti-CREB antibody and analyzed by immunofluorescent confocal microscopy as described in “Methods.” Representative images from 6 fields per slide are shown and are also representative of 3 independent experiments with similar results. (B) Whole-cell lysates from the indicated cells were subjected to SDS-PAGE and western blot analysis of the indicated proteins; a representative blot of 3 similar experiments is shown. (C) Relative CREB protein levels (mean ± SE from 3 independent experiments as in panel B) were quantified, with levels in parent M12.4.1 cells set as 1. *P = .01 (Student t test; see “Methods”).