Changes in beta-tubulin isoforms and their RNA level in synchronized tobacco cells.

Tobacco BY-2 cells were synchronized by an aphidicolin treatment, and their beta-tubulin isoforms and their mRNA were analyzed by Western, Northern and dot blottings. The relative ratio of the beta-tubulin isoforms changed with the progress of cell cycle stage. By Northern blot hybridization of poly(A)+RNAs with a cloned carrot beta-tubulin cDNA probe, a single band of about 1.6 kb was detected throughout the cell cycle. Dot blot hybridization showed that beta-tubulin mRNA existed in all stages in the cell cycle at a relatively constant level, though it accumulated slightly more than average at M phase and decreased during G1 phase.