Two-dimensional PAGE of whole RV-SMC cells (A; 5 × 106 cells) and pachytene spermatocytes of the rat (B, C; 5 × 106 cell/gel). After transfer to nitrocellulose, the proteins were incubated with mAb PKB8 against lamins A, B1, and C (A and B) or mAb R27 against lamins A, C, and C2 (C).