Hans-Georg Simon, PhD

Associate Professor of Pediatrics
Feinberg School of Medicine

Director of Pre- and Postdoctoral Research Training Program
Children’s Memorial Research Center

Research Interests:
As candidates for genes that are involved in shaping our arms (forelimbs) and legs (hindlimbs) Dr. Simon’s laboratory has previously isolated members of a family of evolutionary conserved, so called T-box transcription factors. The forelimb-specific Tbx5 and the hindlimb-specific Tbx4 genes appear to be important in limb initiation and outgrowth as well as limb-type specification. The same two transcription factors have also crucial functions in heart development, and when mutated in humans, both genes cause severe birth defects characterized by upper limb and heart septation defects (Holt-Oram Syndrome) or patella, hip, and foot malformations (Small Patella Syndrome), respectively.

The main focus in the lab is to find out how the same transcription factors orchestrate different functional activities in developing limbs and hearts using mouse, chicken, and zebrafish model systems. In addition to these developmental studies, the lab is interested in discovering the genes that are involved in regenerative processes. As models for these investigations zebrafish and urodele amphibians are employed, which can regenerate limbs and heart ventricles throughout their life times. The identification of genetic pathways that are operational in these regenerating species but not in mammals, will provide new insights into how to restore regenerative abilities in non-regenerating species including humans.

Selected Publications:
Kulisz, A. and Simon, H. G. (2008). An evolutionarily conserved nuclear export signal facilitates cytoplasmic localization of the Tbx5 transcription factor. Mol Cell Biol 28, 1553-64.

Bimber, B., Dettman, R. W. and Simon, H. G. (2007). Differential regulation of Tbx5 protein expression and sub-cellular localization during heart development. Dev Biol 302, 230-42.

Camarata, T., Bimber, B., Kulisz, A., Chew, T. L., Yeung, J. and Simon, H. G. (2006). LMP4 regulates Tbx5 protein subcellular localization and activity. J Cell Biol 174, 339-48.

Isphording, D., Leylek, A. M., Yeung, J., Mischel, A. and Simon, H. G. (2004). T-box genes and congenital heart/limb malformations. Clin Genet 66, 253-64.

Krause, A., Zacharias, W., Camarata, T., Linkhart, B., Law, E., Lischke, A., Miljan, E. and Simon, H. G. (2004). Tbx5 and Tbx4 transcription factors interact with a new chicken PDZ-LIM protein in limb and heart development. Dev Biol 273, 106-20.