Antisense p21 mRNA expression and its effect on p21 protein levels. (A) The top picure is a Northern blot hybridization of p21 mRNA expression from parental (MO7e), LXSN (vector control), and AS21(antisense p21) cells visualized with probe specific to human p21. The lower picture is ethidium bromide staining of the same blot to show total RNA loading; 18S and 28S rRNA is indicated. (B) Western blot visualization of p21 protein in lysates from LXSN and AS21 cells probed with monoclonal antibody to human p21 (equal amounts of protein were loaded per lane). Data are representative of two experiments.