The present invention provides mammalian retinoblastoma (Rb) protein-interacting zinc finger (RIZ) proteins, nucleic acid molecules encoding RIZ and antibodies specific for RIZ. The invention provides methods for identifying an agent that alters the association of a RIZ with a second molecule, which can bind to RIZ. The invention provides fragments of RIZ, PRD1-BF1, EVI-1, and egl-43. The invention provides methods for introducing a nucleic acid molecule encoding a RIZ into a cell and for contacting a cell with an effective agent in order to modulate a function of a cell. The invention further provides methods for detecting a RIZ in a sample by detecting RIZ or a nucleic acid molecule encoding RIZ.