Profilin and profilin mRNA in the cerebellum of the developing rat.

Profilin and profilin mRNA concentrations were determined in the cerebellum of the developing rat. Profilin represented nearly 0.1% of total Triton-soluble protein both at birth and at the end of the developmental period. During brain maturation, the profilin concentration was regulated at the transcriptional level. A transient increase of profilin mRNA and profilin was observed at the end of the first postnatal week, a period of intense cell proliferation, neuritic outgrowth and synaptogenesis. We propose that profilin may act by forming, during the critical period of cerebellar development, a reserve pool of monomeric actin that can easily be mobilized in cell regions such as growth cones or synaptic junctions where filamentous actin is highly concentrated.