Roles of TACC-related protein, Mia1p in MTOCs and microtubule dynamics in Schizosaccharomyces pombe

Abstract

Microtubule arrays of distinct geometries are important for cell function.Microtubule-organizing centers (MTOCs) concentrate microtubule nucleation,attachment and bundling factors and thus restrict formation of microtubule arrays inspatial and temporal manner. It is essential to understand molecular mechanismsunderlying MTOC emergence and maintenance. In this thesis, I use a combination of cellimaging, cell manipulation and genetics experiments in the fission yeastSchizosaccharomyces pombe, to show that the Transforming Acidic Coiled Coil protein,Mia1p, functions in sustaining proper MTOC and microtubule dynamics, both ininterphase and mitosis. Briefly, I show that Mia1p is required for microtubule attachmentto the nucleation sites. Furthermore, when overexpressed, Mia1p organized ectopicspindle pole like structures that interfered with normal mitotic spindle assembly. Thesestudies led us to identify a role for the spindle pole bodies in segregation of the nuclearenvelope during closed mitosis.