Tubuiin gene expression in the Chlamydomonas reinhardtii cell cycle: elimination of environmentally induced artifacts and the measurement of tubuiin mRNA levels

To investigate the involvement of tubuiin gene expression in controlling cell division events in Chlamydomonas reinhardtii we have measured tubuiin mRNA levels during the cell cycle under different environmental conditions. In C. reinhardtii cells grown under the synchronizing conditions of 14 h of light followed by 10 h of darkness, mRNAs for tubuiin and associated flagellar proteins were found to accumulate periodically with a peak just prior to cell division. This was not seen when previously synchronized cells were transferred to constant environmental conditions in a turbidostat, suggesting that dramatic changes in tubuiin mRNA levels are not required for successful completion of the cell cycle. A hypothesis to explain the patterns of tubuiin mRNA accumulation found under different environmental conditions is presented.