Work

Differing requirements for Augmin in male meiotic and mitotic spindle formation inDrosophila

Year: 2014

Type: article

Abstract: Animal cells divide using a microtubule-based, bipolar spindle. Both somatic, mitotic cells and sperm-producing male meiotic spermatocytes use centrosome-dependent and acentrosomal spindle-forming mechanisms. Here, we characterize the largely undefined, centrosome-independent spindle formation pathway used during male meiosis. Our live and fixed cell analyses of Drosophila spermatocytes reveal that acentrosomal microtubules are nucleated at kinetochores and in the vicinity of chromatin and that together these assemble into functional spindles. Mutational studies indicate that γ-tubulin and its extra-centrosomal targeting complex, Augmin, are vital for this process. In addition, Augmin facilitates efficient spindle assembly in the presence of centrosomes. In contrast to the pronounced recruitment of Augmin on spindles in other cell types, the complex is absent from those of spermatocytes but does accumulate on kinetochores. Polo kinase facilitates this kinetochore recruitment while inhibiting Augmin's spindle association, and this in turn dictates γ-tubulin distribution and spindle density. Polo's negative regulation of Augmin in male meiosis contrasts with its requirement in loading Augmin along mitotic spindles in somatic Drosophila cells. Together our data identify a novel mechanism of acentrosomal spindle formation in spermatocytes and reveal its divergence from that used in mitotic cells.

Source: Open Biology

DOI: 10.1098/rsob.140047

Authors: Matthew S. Savoian, David M. Glover

Institution: University of Cambridge

Language: English

Topic: Microtubule and mitosis dynamics

Subfield: Cell Biology

Field: Biochemistry, Genetics and Molecular Biology

Domain: Life Sciences

Open Access status: gold

Estimated APC paid: $1,839

Funder: Cancer Research UK