Distribution of precursor and spliced construct RNA in the nucleus and cytoplasm of S194. A high but equal amount of precursors is present in nuclear RNA for all three constructs (βAPr-Bcl-2, βAPr-Ig, and βAPr-Ig▵introns), whereas spliced RNA is predominantly present in βAPr-Ig(nucleus and cytoplasm). Precursor bands in the cytoplasm represent low-level contamination with nuclear RNA.