Mazur and Brugus worked with Daniel Needleman, Assistant Professor of Applied Physics and Molecular and Cellular Biology at Harvard, and Valeria Nuzzo, a former postdoctoral fellow in Mazur's lab at SEAS, to bring the tools of applied physics to bear on a biological question.
The team used a femtosecond laser to make two small slices perpendicular to the plane of growth of the spindle apparatus in egg extracts of the frog species Xenopus laevis.
They were then able to collect quantitative data on the reconstruction of the spindle following this disruption and precisely determine the length and polarity of individual microtubules. Observing the speed and extent of depolymerization (unraveling) of the spindle, the team worked backwards to compile a complete picture of the beginning and end points of each microtubule. Finally, additional experiments and a numerical model confirmed the role of transport.
"The laser allowed us to make precise cuts and perform experiments that simply were not possible using previous techniques," says Mazur.
With further inquiries into spindle architecture, the researchers hope that scientists will one day have a complete understanding, and possibly even control over, the formation of the spindle.
"Understanding the spindle means understanding cell division," notes Brugus. "With a better understanding of how the spindle is supposed to operate, we have more hope of tackling the range of conditionsfrom cancer to birth defectsthat result from disruptions to the cell cycle or from improper chromosomal segregation."
|Contact: Caroline Perry|