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16.10.17 Role for dynactin in protecting microtubules to deliver oskar mRNA to the oocyte posterior

last modified Nov 13, 2017 10:27 AM
In this eLife paper the St Johnston lab with Cambridge colleagues describe a role for dynactin as an 'anti-catastrophe' factor in oocyte polarisation
16.10.17 Role for dynactin in protecting microtubules to deliver oskar mRNA to the oocyte posterior

Fig. 9 (excerpt) Model of the kinesin1/dynactin/microtubule positive feedback loop.

Localised dynactin protects growing microtubules to deliver oskar mRNA to the posterior cortex of the Drosophila oocyte

Nieuwburg R et al. (2017) eLife 6:e27237 DOI:10.7554/eLife.27237

Abstract

The localisation of oskar mRNA to the posterior of the Drosophila oocyte defines where the abdomen and germ cells form in the embryo. Kinesin 1 transports oskar mRNA to the oocyte posterior along a polarised microtubule cytoskeleton that grows from non-centrosomal microtubule organising centres (ncMTOCs) along the anterior/lateral cortex.

Here, we show that the formation of this polarised microtubule network also requires the posterior regulation of microtubule growth. A missense mutation in the dynactin Arp1 subunit causes most oskar mRNA to localise in the posterior cytoplasm rather than cortically. oskar mRNA transport and anchoring are normal in this mutant, but the microtubules fail to reach the posterior pole.

Thus, dynactin acts as an anti-catastrophe factor that extends microtubule growth posteriorly. Kinesin 1 transports dynactin to the oocyte posterior, creating a positive feedback loop that increases the length and persistence of the posterior microtubules that deliver oskar mRNA to the cortex.

 

Read more about research in the St Johnston lab.

Studying development to understand disease

The Gurdon Institute is funded by Wellcome and Cancer Research UK to study the biology of development, and how normal growth and maintenance go wrong in cancer and other diseases.

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