The present invention encompasses novel mammalian cell cycle checkpoint genes/DNA repair genes, cDNA or genomic DNA, isolated nucleic acids corresponding thereto, expression vectors comprising said nucleic acids, host cells transformed with said expression vectors, pharmaceutical compositions and the formulation of such compositions comprising said nucleic acids or proteins expressed therefrom, methods for treating a cell using such nucleic acids, proteins or pharmaceutical compositions, and the use of such nucleic acids or proteins in formulating a pharmaceutical preparation.