CHARACTERIZATION OF PR DOMAIN PROTEINS AND THEIR BINDING PARTNERS

Members of the PRDM protein family play important roles in stem cells and cellular differentiations. Several PRDM proteins have also been related to cancer. The PRDM proteins affect cellular differentiation by regulating gene transcription, but the underlying molecular mechanism is not yet clear. Herein, we tried to address this question by studying the molecular basis of the proposed histone methyltransferase activity of several PRDM proteins, as well as the interactions between PRDM proteins and other nuclear proteins. By using NMR spectroscopy and other biochemistry techniques, we found that, except for PRDM9, all the other PRDM proteins bind substrate and cofactors only with very low affinities, and mediate histone methyltransferase inefficiently by themselves. Therefore, the PRDM proteins might require interactions with other unknown macromolecules to exert their functions