Functional analysis of the Drosophila microtubule regulator mini spindles

• Main Author: Brittle, Amy
• Published: University of Edinburgh 2005
• Subjects: 572.8
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.641952

The <i>Drosophila</i> gene, <i>mini spindles (msps), </i>is a member of a family of proteins involved in microtubule regulation. The protein has a defined structure; however, the roles of the different domains of the protein are unknown. Previous studies have demonstrated that Msps protein is essential for bipolar spindle formation in both mitosis and female meiosis; however, its role in interphases microtubule regulation has not been defined. The aim of this study was to related different regions of Msps protein to specific functions and to investigate the role of Msps in interphases microtubule regulation. In this study the function of different regions of the protein were examined by the creation and analysis of new <i>msps</i> alleles. Analyses of one allele, <i>msps⁵¹,</i> indicated that the C-terminal region is essential for centrosomes localisation and for the protein to bind to the centrosomes associated protein, D-TACC. Msps depletion from <i>Drosophila</i> culture cells (S2 cells) revealed a dramatic role for Msps in interphases microtubule organisation. In the depleted cells microtubules could no longer extend to the cell cortex and frequently bundled microtubules were seen. This phenotype was investigated by the analysis of microtubule dynamics in live cells. Msps was found to increase the dynamicity of the microtubules by acting as an anti-pause factor.  Msps function in interphases microtubule regulation was demonstrated to be independent of known Msps interactors, D-TACC and the KinI destabilising kinesins. This study demonstrates that Msps plays an essential role in the regulation of interphase microtubules in addition to organising the bipolar spindle.