Segurem os centrosomos

The Scientist

Volume 23 | Issue 11 | Page 55

By Bob Grant

Hold the centrosomes

The paper:

R. Basto et al., “Centrosome amplification can initiate tumorigenesis in flies,” Cell, 133:1032–42, 2008. (Cited in 32 papers)

The finding:

Tumor cells display both chromosomal instability and centrosome amplification, in which they have extra copies of the organelles that orchestrate the movement of microtubules and the progression through the cell cycle. But last year, a group led by researchers at the Gurdon Institute in the United Kingdom found that centrosome amplification alone is enough to incite tumor growth.

The missing step:

Cell biologist Jordan Raff and his colleagues developed a line of Drosophila that had extra centrosomes in 60% of their cells but largely normal chromosomes. “It was a big deal that they separated centrosome amplification from chromosome abnormalities,” says William Saunders, a University of Pittsburgh cell biologist who was not involved with the study.

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Read more here/Leia mais aqui.

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NOTA DESTE BLOGGER:

Em 2005, Jonathan Wells, Ph. D. em Biologia Molecular, um dos teóricos do Design Inteligente, escreveu o artigo "Do Centrioles Generate a Polar Ejection Force?"

1. Introduction
2. Centriole Structure and Function
3. Dynamics of a Centriole Pair
4. A Polar Ejection Force
5. Regulation by Intracellular Calcium
6. Implications for Cancer
7. Conclusions

Abstract. A microtubule-dependent polar ejection force that pushes chromosomes away from spindle poles during prometaphase is observed in animal cells but not in the cells of higher plants. Elongating microtubules and kinesin-like motor molecules have been proposed as possible causes, but neither accounts for all the data. In the hypothesis proposed here a polar ejection force is generated by centrioles, which are found in animals but not in higher plants. Centrioles consist of nine microtubule triplets arranged like the blades of a tiny turbine. Instead of viewing centrioles through the spectacles of molecular reductionism and neo-Darwinism, this hypothesis assumes that they are holistically designed to be turbines. Orthogonally oriented centriolar turbines could generate oscillations in spindle microtubules that resemble the motion produced by a laboratory vortexer. The result would be a microtubule-mediated ejection force tending to move chromosomes away from the spindle axis and the poles. A rise in intracellular calcium at the onset of anaphase could regulate the polar ejection force by shutting down the centriolar turbines, but defective regulation could result in an excessive force that contributes to the chromosomal instability characteristic of most cancer cells.

Keywords. Centriole; Centrosome; Polar ejection force; Chromosomal instability;
Cancer.

Rivista di Biologia / Biology Forum 98 (2005), pp. 71-96.

PDF grátis do artigo aqui.