Figure 1. Expression of the PLCß₁ isoform during differentiation of primary human gingival fibroblasts. (A) Cells underwent lysis as described in MATERIALS & METHODS, and were subjected to SDS-PAGE, blotted, and immunoprobed with anti-PLCß₁ antibody. A 20-µg quantity of protein was loaded for each lane. The results shown are representative of at least 3 independent determinations. (B) PLCß₁ expression in purified nuclei from primary cultures of different fibroblasts populations. A 20-µg quantity of protein was loaded for each lane. (C) ß tubulin levels were used for normalization. The immunochemical analysis by Western blot on total homogenate and nuclear fraction does not give information on the precise localization of the enzyme, while, at the TEM level, the intranuclear and the intracytoplasmic distributions of the PLCß₁ can be determined with high accuracy, and quantitative variations of the label distribution can be further investigated.