Graham Charles Walker

Biosketch

Graham C. Walker is an American Cancer Society Professor and HHMI Professor in the Department of Biology, Massachusetts Institute of Technology. He is recognized for his basic research on cellular responses to DNA damage and on how mutations occur as a consequence of DNA damage. His work has had a special focus on the regulation and function of the specialized DNA polymerases that carry out translesion DNA synthesis (TLS) in bacteria and in eukaryotes. He is also known for his work on the bacterial-host interactions that underlie the Rhizobium-legume symbiosis, research that has unexpectedly also offered insights into chronic mammalian pathogens, vitamin B12 biosynthesis, and RNA metabolism. Born in Arlington, MA in 1948, he grew up in Ottawa, Canada and received his Honors B.Sc. in chemistry from Carleton University. After receiving his Ph.D. in chemistry and biochemistry from University of Illinois, he did postdoctoral work in bacterial genetics at the University of California, Berkeley before joining the MIT faculty in 1976. In addition to his research, he has been recognized for his leadership in improving undergraduate education in the biological sciences. He has served as the Editor-in-chief of J. Bacteriol. and is a co-author of the textbook, DNA Repair and Mutagenesis (ASM Press).

Research Interests

Dr. Walker's research helped make the bacterial SOS response a paradigm for how cells respond to DNA damage, while his studies of the umuDC and dinB gene products laid the groundwork for the discovery of the Y family of TLS DNA polymerases. His current interests in bacterial DNA repair include determining the biological roles of DinB (DNA pol IV), investigating a previously unrecognized NusA-dependent pathway of transcription-coupled repair, and elucidating how the incorporation of oxidized nucleotides into DNA contributes to the cytotoxic and mutagenic effects of antibiotics. His current research on eukaryotic TLS DNA polymerases focuses on whether interfering with the Rev1/3/7-dependent branch of mutagenic translesion synthesis could help to improve chemotherapy. His work on the Rhizobium-legume symbiosis seeks to understand the molecular mechanisms by which defensin-like nodule-specific cysteine rich (NCR) peptides alter the bacterial cell cycle to undergo rounds of endoreduplication and force terminal differentiation into nitrogen-fixing bacteroids. His discovery of its symbiotic role stimulated him to discover that YbeY is previously unrecognized important metal-dependent endoribonuclease that is present in almost all bacteria and plays central roles in RNA metabolism. He is currently investigating YbeY's role in 16S rRNA processing, 70S ribosome quality control, and small RNA regulation.