Evidence for rapid structural and functional changes of the melanophore microtubule-organizing center upon pigment movements.

摘要: Melanophores of the angelfish, pterophyllum scalare, have previously been shown to display approximately 2,400 microtubules in cells wih pigment dispersed; these radiate from a presumptive organizing center, central apparatus (CA), and their number is reduced 1,000 state with aggregated (M. Schliwa U. Euteneuer, 1978, J. Supramol. Struct. 8:177-190). In an attempt elucidate factors controlling this rapid reorganization microtubule apparatus, structure function CA investigated under different physiological conditions. As distribution, melanophores differ markedly respect organization. A complex dense amorphous aggregates associated fuzzy material, several micrometers diameter, surrounds centrioles dispersed, numerous emanate radial fashion. state, on other hand, few are observed pericentiolar region, amount fibrous material greatly reduced. These changes morphology as distribution marked difference its capacity initiatiate assembly exogenous pure porcine brain tubulin lysed cell preparations. After complete removal preexisting microtubules, dispersed into solution 1-2 mg/ml fashion, while nucleate only microtubules. We conclude that it activity basically regulates expression This regulation achieved through variation initiate assembly. Increase or decrease readily system studied here, seems be morphologic such physiologic function.