Effect of aspartic acid substitutions on cytoplasmic localization of complete basonuclin. (A) A keratinocyte culture (YF29) growing in the presence of 3T3 support was transfected with plasmid (pHUB4), encoding FLAG-basonuclin bearing serine substitutions. After 18 hr, the number of cells with cytoplasm stained by anti-FLAG antibody was scored. Total number of cells scored for each transfection was: SSS, 73; SDS, 67; DSS, 61; SSD, 93; DSD, 71. Substitutions at Ser-540 and Ser-541 led to an increase in number of cells with stained cytoplasm.