Meeting Abstract

P1.43  Monday, Jan. 4  The expression of spindle assembly checkpoint protein Bub-1 in zebrafish (Danio rerio) oocytes. WOOD, Mandi J*; DEMARAIS, Alyce; Univ. of Puget Sound; Univ. of Puget Sound mwood@ups.edu

Chromosome segregation is highly regulated and the spindle assembly checkpoint is a conserved cell cycle surveillance mechanism that regulates the fidelity of this process. In mitosis, a single unattached kinetochore activates the checkpoint to signal a periodic arrest of the cell cycle in metaphase. This arrest of the cell cycle is a crucial stage in oocyte development and is followed by completion of meiosis and the prevention of aneuploidic genomes or hyper-prolific daughter cells. Several checkpoint genes have been identified in budding yeast including Bub-1. These proteins are thought to play lead roles in a MAPK-regulated pathway for checkpoint activation as a response to microtubule defects. Previously, studies on this checkpoint have been performed in mammals and amphibians. The present study shows the involvement of Bub-1 in zebrafish (Danio rerio) oocyte development. Zebrafish oocytes were treated with Nocadozole, a microtubule depolymerizing drug, to activate the spindle assembly checkpoint. Protein and RNA assays revealed that Bub-1 is present in D. rerio and appears to be regulated in both Nocadozole- and progesterone-treated oocytes. Levels of Bub-1 were higher under microtubule destabilization by Nocadozole, suggesting that the Bub-1 protein could be activated in response to microtubule instabilities. Further studies will lend a greater understanding of the relationship of the Bub-1 gene with the spindle assembly checkpoint in D. rerio oocytes. This arrest of the cell cycle is a crucial stage in oocyte development and maturation prior to successful fertilization.