This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. The yeast spindle pole body (SPB) is functionally equivalent to the centrosome in higher eukaryotic cells. The SPB is a multilayered organelle that organizes both the nuclear and cytoplasmic microtubules. We are working toward reconstitution of the microtubule nucleating activity of the SPB. The well characterized small gamma-tubulin complex contains three proteins: Tub4p, Spc97p, and Spc98p. We have expressed all three proteins in baculovirus and found that they readily assemble into a stable, soluble complex. However, the nucleation capacity of the small complex is quite low, suggesting we are missing components required for nucleation. We have recently found that gamma-tubulin and Spc97p are also present as part of larger complex in yeast cells. We are interested in characterizing this complex in collaboration with the Yeast Resource Center.