Identification of Pathways Required for the Coordination of Late Mitotic Events in Animal Cells

Abstract

Abstract : The temporal coordination of anaphase, cytokinesis and mitotic exit is essential for the production of viable daughter cells, and mutations that affect the proper timing of these events result in genomic instability, a hallmark of cancer. In yeast, a signaling pathway has been identified, called the Mitotic Exit Network, which coordinates mitotic exit and cytokinesis with the end of anaphase. Homologues of three of these signaling components have been identified in humans suggesting that human cells regulate mitosis in a similar fashion; however, a clear mitotic exit network has yet to be revealed. The identification and characterization of such a pathway in human cells will further our understanding of how normal cell division is regulated and will highlight possible mechanisms of genomic instability in tumor cells. In order to discover those genes that are involved specifically in animal cell division and are not conserved in yeast, we are taking advantage of the nematode, C. elegans. C. elegans is a multi-cellular complex metazoan whose genes are more homologous to humans than are those of yeast. This system will allow for the rapid functional analysis of large numbers of candidate genes that can then be used to ascertain their human counterparts by sequence comparison. Using the yeast two-hybrid system we have built a protein interaction map for hundreds of candidate C. elegans genes that are potentially involved in mitotic temporal control, based on phenotypic data as well as homology to yeast genes of known function. Once complete, these interaction data in combination with phenotypic data will help to elucidate specific biochemical pathways involved in late mitotic events. By recognizing the components of these putative pathways novel targets for anti-cancer therapies may be discovered. This report summarizes work done over the past twelve months, which culminated in the drawing of a preliminary mitotic protein interaction map for C. elegans.