Whole-cell extracts of HeLa cells expressing each EGFP-containing construct were separately resolved by SDS/PAGE and identified by Western blots with anti-EGFP antibody. The non-transfected HeLa cells were used as a negative control. Expressed EGFP of molecular mass 28 kDa was used as the marker indicated by the arrow. (A) Lanes: a, preOTCsp–EGFP-ER; b, preOTCsp–EGFP; c, EGFP; d, untransfected cells. (B) Lanes: a, preAIIsp–EGFP-ER; b, preAIIsp–EGFP; c, EGFP; d, untransfected cells. (C) Lanes: a, preOTCsp–EGFP–SKL; b, EGFP–SKL; c, EGFP; d, untransfected cells.