Cell motility and the cytoskeleton Jan 10, Movement and positioning of melanophore pigment organelles depend on microtubule- and actin-dependent motors, but the regulation of these forces are poorly understood. Here, we describe a cell free and fixed time motility assay for the study of the regulation of microtubule-dependent pigment organelle positioning in vitro.
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Abstract The microtubule system of melanophores of the angelfish, Pterophyllum scalare, has been studied using antibodies prepared against purified porcine brain tubulin in indirect immunofluorescence microscopy. Melanophores were freed from the surrounding tissue components of isolated scales by mild enzymatic digestion and then allowed to settle on a glass cover slip.
In both the dispersed and the aggregated states large numbers of fluorescent fibers are seen.
The number and the astral arrangement of these fibers, which run from the central region to the periphery of the cell, are striking.
The system of fluorescent fibers is replaced by diffuse fluorescence of moderate intensity after cold treatment, but is restored after rewarming the cells. Differences in the immunofluorescence profiles between cells with dispersed and aggregated pigment are discussed in relation to electron microscopic data available for this system.
Selected References These references are in PubMed. This may not be the complete list of references from this article.
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Cytoplasmic microtubules in tissue culture cells appear to grow from an organizing structure towards the plasma membrane.
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Griseofulvin interacts with microtubules both in vivo and in vitro.We report here that virtually all microtubules in the RPE apical projections are uniformly oriented with plus ends toward the cell body and minus ends toward the projection tips.
This orientation is opposite that found for microtubules of dermal melanophores, neurons, and most other cell types. Dec 14, · Melanophores move pigment organelles (melanosomes) from the cell center to the periphery and vice-versa.
These bidirectional movements require cytoplasmic microtubules and microfilaments and depend on the function of microtubule motors and a myosin. Abstract. When microtubules in teleost melanophores are disrupted with antimitotic agents, colchicine, high hydrostatic pressure, low temperature, and vinblastine, the alignment and movement of the pigment granules in these cells disappear; during recovery, the return of alignment and movement corresponds in both time and space with the repolymerization of microtubules.
Melanophores were incubated at 0°C in the presence of 10 μg/ml nocodozole to induce microtubule depolymerization or perfused with 5 μM latrunculin A or 20 μg/ml cytochalasin B to depolymerize filamentous actin, and individual cells were imaged using video-enhanced time-lapse microscopy.
In the absence of microtubules, melanosomes in.
|References||Hydroquinone is used as a skin-lightening agent, it is also present in different chemical products and cigarette smoke. It is believed to inhibit melanin production in melanocytes by inhibiting the key enzyme tyrosinase.|
Movements associated with microtubules are responsible for separating chromosomes during cell division and for driving axoplasmic transport. We study intraflagellar transport (IFT), a process which by material is transported along the microtubules of cilia and flagella. Abstract. Abstract.
The microtubule motors, cytoplasmic dynein and kinesin II, drive pigmented organelles in opposite directions in Xenopus melanophores, but the mechanism by which these or other motors are regulated to control the direction of organelle transport has not been previously elucidated.