Effect of Lithium on Flagellar Length in Chlamydomonas reinhardtii

抄録

We have found that Li⁺ causes the flagella of Chlamydomonas reinhardtii to elongate. After incubation with 50 mM Li⁺ for 3-4 hr, flagellar length increased to about 1.4 times the original length. However, the addition of 50 mM Li⁺ after flagellar amputation caused the regeneration of only half-length flagella, similar to those regenerated in the presence of 20 μg/ml cycloheximide. When regenerated flagella grown in the presence of either Li+ or cycloheximide were re-amputated, they did not regrow. These results suggest that (1) Li⁺ removes a suppressor(s) in the regulatory mechanism which normally controls flagellar length, (2) flagellar length may exceed a length-dependent "maximum" value (Tamm, S. L., 1967, J. Exp. Zool., 164, 163-186), and (3) Li⁺ inhibits the protein synthesis required for the complete regeneration of flagella. Thus, normal flagella elongate to 1.4 times their original length in the presence of 50 mM Li⁺ by using flagellar precursors from a preexisting cytoplasmic pool.