Robert M. Johnson, Ph.D.

My lab is interested in two different areas, although both have something to do with the human erythrocyte. We work on the effect of oxidative damage on erythrocyte function, using mice with a genetically engineered deletion of enzymes of oxidative defense. These mice are prepared by Dr. Ye-Shih Ho of our department. Dr. Ho is also a member of Wayne’s Institute of Toxicology. In addition, we work on the control of hemoglobin transcription, using a comparative and evolutionary approach. The polypeptide composition of hemoglobin changes during embryonic development. This is called "globin switching". Our approach is to examine the switch in primate species closely related to humans, in which the switching program is subtly different. By examining promoter regions from genes that turn on at different points in embryogenesis, we are able to pinpoint promoter changes that mediate the timing of the developmental switch.

Opazo, J.C., Wildman, D.E., Prychitko, T., Johnson, R.M., and Goodman, M. Phylogenetic relationships and divergence times among New World monkeys (Platyrrhini, Primates). Molecular Phylogenetics and Evolution 40:274-280, 2006

Johnson, R.M., Prychitko, T., Wildman, D.E., Uddin, M., Gumucio, D., and Goodman, M. Phylogenetic comparisons suggest distance from the locus control region guides developmental expression of primate β-type globin genes. Proc. Natl. Acad. Sci. USA 103:3186-3191, 2006

Johnson, R.M, Goyette, G., Ravindranath, Y., and Ho, Y-S. Hemoglobin autoxidation and regulation of endogenous H₂O₂ levels in erythrocytes. Free Rad. Biol. Med. 39:1407-1417, 2005

Prychitko, T., Johnson, R.M., Wildman, D.E., Gumucio, D., and Goodman, M. The phylogenetic history of New World monkey β-globin reveals a platyrrhine to gene conversion in the atelid ancestry. Molecular Phylogenetics and Evolution 35:225-234, 2005.

Uddin M, Wildman DE, Liu G, Xu W, Johnson RM, Hof PR, Kapatos G, Grossman LI, and Goodman M. Sister-grouping of chimpanzees and humans as revealed by genome-wide phylogenetic analysis of brain gene expression profiles. Proc. Natl. Acad. Sci. USA. 101:2957, 2004.

Johnson. R.M., Gumucio, D. L., and Goodman, M.. Globin Gene Switching in Primates. Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology 133:877-883, 2002.

Johnson, R.M, Goyette, G. Ravindranath, Y., and Ho, Y-S. Oxidation of glutathione peroxidase deficient red cells by organic peroxides. Blood 100:1515-1516, 2002.

Johnson, R.M., Buck, S., Chiu, C.-H., Gage, D.A., Shen, T-L., Hendrickx, A.G., Gumucio, D. L., and Goodman, M. Humans and Old World monkeys have similar patterns of fetal globin expression. J. Exp. Zool. (Mol.Dev. Evol.) 288:318-326, 2000.

Johnson, R.M, Goyette, G. Ravindranath, Y., and Ho, Y-S. Red cells from glutathione peroxidase-1 deficient mice have nearly normal defenses against exogenous peroxides. Blood 96:1985-1988, 2000.

Johnson, R.M, Panchoosingh, H., Goyette, G. and Ravindranath, Y. Increased deformability in fetal erythrocytes: its occurrence in glycolytic enzyme deficiencies and accelerated erythropoiesis. Ped. Res. 45:106-113, 1999.

Johnson. R.M., Buck, S., Schneider, H., Sampaio, I., Gage, D.A., Shen, T-L., Schneider, M.P.C., Muniz, J.A., Gumucio, D. L., and Goodman, M. Fetal globin expression in New World monkeys. J. Biol. Chem. 271:14684-14691, 1996.

Johnson, R.M. and Ravindranath, Y. Osmotic scan ektacytometry in clinical diagnosis. J. Ped. Hem. Onc., 18:122-129, 1996.