Analysis of chimeric receptor expression in undifferentiated ES cells by RNase mapping and by FACS analysis.

(A) Expression of chimeric receptors (clone PR1 for P-R, clones PE1 and PE2 for PE-R, clones PM1 and PM2 for PM-R) after CJ7 cell electroporation, by RNase mapping. CJ7 and CJ7 MSCV RNAs were used as negative controls. Actin RNA expression was used as an internal control. A comparison of PM-R expression after ES cell electroporation or after viral infection (PMI) is also shown. (B) ES cell surface expression of chimeric receptors was determined by FACS analysis using M110 monoclonal antibody. Undifferentiated ES cells were dissociated with Accutase (PAA Laboratories, Les Mureaux, France) prior to incubation with the antibody. The percentage of ES cells expressing P-R, PE-R, and PM-R is indicated.