[Expressions of cyclins A, B1, D3, and E in asynchronous and synchronous MOLT-4 cells of G1 phase].

BACKGROUND & OBJECTIVE: We have testified expression imbalance of Cyclins A, B1, D3, and E in MOLT-4 cells, which were synchronized by "double thymidine blocks", with flow cytometry (FCM). However, comparisons of Cyclins expressions between synchronized cells and asynchronized cells haven't been performed at that time because of technique limitations. This study was to compare expressions of Cyclins A, B1, D3, and E in G(1) phase of asynchronized and synchronized cells by newly established "postsorting Western blot", and to conform the unreasonableness of using double thymidine blocks to synchronize cells to analyze normal cell cycles. METHODS: MOLT-4 cells were synchronized at G(1) phase by double thymidine blocks, asynchronous cells of G(1) phase were sorted by FCM. Western blot and double parameters analysis of DNA/Cyclins were performed to detect Cyclins A, B1, D3, and E expressions in asynchronous and synchronous MOLT-4 cells of G(1) phase. RESULTS: There were almost no expressions of Cyclins A, B1 in asynchronous MOLT-4 cells of G(1) phase, and obvious expressions in synchronized cells of G(1) phase. Expressions of Cyclins D3, E in synchronous MOLT-4 cells of G(1) phase were higher than those in asynchronous cells of G(1) phase. The FCM results were accordant with Western blot results. CONCLUSIONS: The expressions of Cyclins in synchronized cells obtained through "double thymidine blocks" can't represent their expressions in normal cells. Thus, synchronous cells produced by "double thymidine blocks" are not ideal experimental models for analyzing normal cell cycles.