Cell cycle stage-specific accumulation of mRNAs encoding tubulin and other polypeptides in Chlamydomonas

The accumulation pattern of a number of mRNAs during the cell cycle of Chlamydomonas was examined by two-dimensional gel analysis of in vitro translation products and by RNA blot hybridization analysis. Two-dimensional gel analysis revealed that 10-15% of the 300 most abundant translation products are differentially synthesized from RNA obtained at various cell cycle stages. RNAs that direct the synthesis of alpha- and beta-tubulins and that hybridize to cloned alpha- and beta-tubulin probes accumulate coordinately during the predivision period of the cell cycle, reaching peak levels before or during division. Other RNAs represented by selected cloned cDNA probes show a number of different cell cycle patterns of accumulation. The accumulation patterns of these RNAs are not directly influenced by ongoing illumination conditions, even though alternating light-dark illumination cycles are used to synchronize Chlamydomonas cells. The results suggest that there may be a complex program of gene expression correlated with cell cycle progression in Chlamydomonas.