Rapid changes in tubulin RNA synthesis and stability induced by deflagellation in Chlamydomonas

Detachment of the flagella of Chlamydomonas induces a rapid accumulation of mRNAs for tubulin and other flagellar proteins. Measurement of the rate of alpha and beta tubulin RNA synthesis during flagellar regeneration shows that deflagellation elicits a rapid, 4-7-fold burst in tubulin RNA synthesis. The synthesis rate peaks within 10-15 min, then declines back to the predeflagellation rate. Redeflagellation of cells at times before the first flagellar regeneration is completed (and when cells have already accumulated elevated levels of tubulin RNA) induces another burst in tubulin RNA synthesis which is identical to the first in magnitude and duration. This finding indicates that the induction signal may act to simply reprogram the tubulin genes for a transient burst of maximal synthesis. Evidence is presented that the stability of the tubulin RNAs changes during regeneration. Stability changes include both an apparent stabilization during regeneration and accelerated decay following regeneration.