John R. Pehrson, PhD

University of California at Berkeley (1981 to 1981) Postdoctoral Fellow Institute for Cancer Research Philadelphia, Pennsylvania (1981 to 1986) Postdoctoral Fellow

We are studying macroH2A core histone variants. These proteins are three times the size of conventional core histones, and have a hybrid structure consisting of a large nonhistone region and a region that closely resembles a conventional histone H2A. There are three macroH2A variants and two macroH2A genes. MacroH2A proteins are preferentially concentrated on the transcriptionally inactive X chromosome of female mammals and certain other domains of heterochromatin, indicating that macroH2As are involved in establishing or maintaining specific domains of transcriptionally silent chromatin. In order to test and expand on this theory, we are examining the effects of macroH2A knockout mutations on gene expression in vivo. We are also examining the distribution of macroH2A1 nucleosomes in order to identify regions of chromatin that are being directly affected by macroH2A.