PRECURSOR OF CYTOPLASMIC ACTIN IN CULTURED DROSOPHILA CELLS

In continuous lines of cultured Drosophila cells 2 forms of cytoplasmic actin, designated II and III, are detected after a 25-120 min pulse label with [35S]methionine. Only actin II accumulates in the cell. With the use of a pulse-chase protocol and 2 dimensional gel electrophoresis, it was found that actin III is synthesized as a precursor of the more stable cytoplasmic actin II. The half-life of actin III was estimated at approximately 50 min.