Before they divide, vertebrate cells copy six billion base pairs of DNA with almost perfect fidelity. We study how they accomplish this amazing feat. We ask how replication machines are assembled and disassembled at the appropriate time and place, and how they overcome DNA damage and other obstacles. Our work sheds light on the etiology of diseases such as cancer, bone marrow failure, aging, and neurodegeneration.

We use Xenopus laevis frog egg extracts, which recapitulate essentially all aspects of genome maintenance and are therefore like a “cell in a test tube.” Using this highly tractable system in combination with classical biochemistry, single molecule imaging, and cell-based studies, we have discovered new DNA replication and repair mechanisms, many of which are mutated in human diseases (see Research).

The Walter laboratory is a welcoming and highly interactive environment. Graduate students and post-doctoral fellows share reagents, expertise, and ideas to reach their common goal of understanding genome maintenance in health and disease. Walter lab alumni are successful in obtaining group leader, post-doctoral, industry, and other positions (see alumni). Post-docs who start their own groups are free to take their projects with them.