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In vitro reconstitution of fish melanophore pigment aggregation
H Nilsson1, W Steffen, R E Palazzo
1Dept. Zoology, Univ. Göteborg, Göteborg, Sweden. nilsson@abacus.mc.duke.edu
Cell Motility and the Cytoskeleton
|December 22, 2000
Summary
This study developed a cell-free assay to investigate pigment organelle positioning. Dynein motor proteins are essential for pigment aggregation and maintaining pigment dispersion in melanophores.
Area of Science:
- Cell biology
- Molecular motors
- Cytoskeletal dynamics
Background:
- Melanophore pigment organelle positioning relies on motor proteins acting on microtubules and actin filaments.
- The precise regulatory mechanisms governing these motor proteins are not fully understood.
Purpose of the Study:
- To develop and utilize a novel cell-free assay to study the regulation of microtubule-dependent pigment organelle positioning.
- To investigate the roles of dynein and dynactin in pigment aggregation and dispersion.
Main Methods:
- Development of a fixed-time motility assay using cell-free extracts from clam oocytes and Fundulus melanophores.
- Introduction of microtubule asters into melanophore lysates with aggregated or dispersed pigment.
- Utilizing anti-dynein intermediate chain antibody (m74-1) to probe dynein and dynactin function.
Main Results:
- Pigment organelles distributed evenly along astral microtubules in dispersed melanophore lysates.
- Pigment organelles accumulated around the centrosome in aggregated melanophore lysates.
- Anti-dynein antibody blocked pigment aggregation and caused pigment depletion from the centrosome.
Conclusions:
- Dynein motor proteins are crucial for pigment aggregation and maintaining pigment dispersion in melanophores.
- The findings suggest a potential role for dynactin in these cytoskeletal motor-dependent processes.
