Profile of Anthony R. Cashmore

Abstract

Ask Anthony Cashmore about the unifying theme of his research career, which has spanned more than four decades on three continents, and he responds, “There was none.” Cashmore, a member of the National Academy of Sciences who recently retired as a professor of biology at the University of Pennsylvania, has spent much of his career studying how light controls gene expression in plants. However, his long journey through science is chronicled in quests as diverse as unraveling the structure of nucleic acids and understanding the biological basis of human behavior. Although Cashmore recently made waves for his provocative stance on the fiercely contested existence of free will, he is best known for identifying plant photoreceptor proteins called cryptochromes, which enable plants and animals to tell circadian time. Anthony R. Cashmore. Discovered by Cashmore in 1993 in Arabidopsis thaliana , a workhorse for plant molecular biology, cryptochromes mediate blue light signaling in plants, helping adjust growth and flowering to the amount and type of light in the plant's surroundings (1). Cashmore found that Arabidopsis cryptochromes have a carboxyl-terminal domain in their primary structure that distinguishes them from related DNA repair enzymes that help fix UV-ravaged DNA. Furthermore, Cashmore showed that the domain, when produced in Arabidopsis seedlings, mediated a constitutive light response, providing clues as to how cryptochromes act (2). Those early findings paved the way for later research showing that cryptochromes control circadian rhythms in people—a discovery that is part of a rapidly growing interest in sleep disorders. Born in Auckland, New Zealand, Cashmore spent much of his youth in Manawaru, a pastoral village 100 miles south of Auckland where his parents owned a general store. Cashmore says, as a boy growing up surrounded by dairy farms, he had no inkling that he would one day pursue science in some …