Jaenisch Laboratory

The goal is to understand epigenetic regulation of gene expression in mammalian development and genetic disease. We focus on the role of DNA methylation in cancer, genomic imprinting, X chromosome inactivation, and the function of methylation in the postnatal brain. We use gene targeting methods to generate embryonic stem cells and mice with targeted gene deletions. Much of our earlier work has been based upon the targeted inactivation of the Dnmt1 gene, which encodes the only known mammalian DNA methyltransferase (MTase). Because DNA methylation deficiency causes early embryonic lethality, we have generated lineage specific knockouts of the gene to study its role in late events such as cancer and the postnatal brain. Finally, we are using mammalian cloning approaches to distinguish epigenetic and genetic alterations of the genome, which may be part of normal or abnormal development.