(A) Specificities of antibodies as revealed by Western blotting. A total of 3 × 10⁴ COS-7 cells were transfected with 4 μg of pME18S (lanes 1, 3, 5, 7, 9, and 11), expression plasmid for AML1 (lanes 2 and 4), or that for PEBP2β (lanes 6, 8, 10, and 12), lysed, and subjected to Western blotting. The blots were probed with anti-AML1 serum (lanes 3 and 4), rabbit anti-PEBP2β serum (lanes 7 and 8), hamster anti-PEBP2β serum (lanes 11 and 12), as well as with the respective preimmune sera (lanes 1 and 2, 5 and 6, and 9 and 10, respectively). The AML1 or PEBP2β protein is indicated by the arrowhead. Molecular weight standards (in kilodaltons) are indicated. (B) (see page 1690) Specificities of antibodies as revealed by immunofluorescence. A total of 3 × 10⁴ COS-7 cells were transfected with 4 μg of pME18S (a, c, e, and g), expression plasmid for AML1 (b and d), or that for PEBP2β (f and h). The cells were analyzed by immunofluorescence labeling with anti-AML1 serum (c and d) or hamster anti-PEBP2β serum (g and h) as well as with the respective preimmune sera (a and b, and e and f, respectively). Original magnification × 600.