Proclivity for constitutive tumors in mice deficient for MAD1 mitotic checkpoint protein

Mitotic arrest deficient protein 1 (MAD1) is a component of the mitotic spindle assembly checkpoint. To understand better MAD1 function, we have created Mad1+/− mice. Mad1−/− mice are embryonic lethal. We find in aging studies that Mad1+/− mice show a significantly higher incidence of constitutive tumors when compared to control wild type (WT) littermates. We will present findings which correlate a proclivity for development of aneuploidy in primary cells with loss of MAD1 function. We will also discuss our thoughts on the mechanistic role played by MAD1 in spindle assembly checkpoint function.