This project focuses on basic cellular transformation events as related to HTLV-I. For this purpose, we study cellular genetic integrity, cell cycle progression and the checkpoints within a cell that guards normal cellular division. Some notable scientific advances from our research program in 2006-2007 include: 1) Evidence for cooperative transforming activity of the human pituitary tumor transforming gene and human T-cell leukemia virus type 1 tax; 2) Heterozygous deletion of mitotic arrest-deficient protein 1 (MAD1) increases the incidence of tumors in mice; and 3) Histone Acetyltransferase hALP and Nuclear Membrane Protein hsSUN1 Function in De-condensation of Mitotic Chromosomes.