Prof. Dr. Dr. h.c. Ulrich Scheer
Ulrich Scheer retired in 2007 after holding the chair of cell and developmental biology at the University of Würzburg for 21 years. His successor Markus Engstler generously offered him a place and the necessary facilities to get on with his work. Ulrich Scheer is a cell biologist with special focus on the functional organization of the cell nucleus. He graduated from the University of Freiburg i.Br. where he also received his Ph.D. in cell biology in 1970. After a three years postdoctoral period at the Institute of Cell Biology in Freiburg, Ulrich Scheer joined the German Cancer Research Center in Heidelberg as assistant professor, interrupted by a one year stay at the University of St. Andrews in Scotland and short term stays at the University of Chicago. Following habilitation in cell biology at the University of Heidelberg (1977), he was appointed full professor at the University of Würzburg in 1986. During his tenure, Ulrich Scheer served as dean of the biological faculty and chairman of the Biocenter (you can download a more formal CV here).
Research synopsis. Ulrich Scheer is interested in the biology of the cell nucleus, both of “normal” somatic cells and of animal oocytes. His favorite biological system is the giant nucleus (germinal vesicle) of amphibian oocytes. He has been studying structural, functional and dynamic aspects of the nuclear envelope with special emphasis on the nuclear pore complexes, the molecular organization of lampbrush chromosomes with their characteristic loops representing transcriptionally highly active gene loci, the functional organization and assembly of the amplified extrachromosomal nucleoli, and ultrastructural aspects of transcriptional complexes using electron microscopic spread preparations (“Miller speads”). To decipher the function of nuclear proteins, he microinjected a series of antibodies into the nucleus of living amphibian oocytes and found, quite surprisingly at those days (1984), that actin appeared to play a critical role in transcriptional processes. Almost two decades later this notion received support by others and nowadays a large body of evidence exists linking nuclear actin to chromatin remodeling and gene transcription by all three classes of RNA polymerase. The major focus of Ulrich Scheer’s current work is to understand the functional organization of nucleoli in mammalian cells and to find out how the cascade of biochemical reactions involved in ribosome biogenesis is spatially organized and integrated into nucleolar structure. By using immunocytochemical approaches, he has identified the fibrillar centers of nucleoli as the sites where the transcriptionally active rRNA genes are located. Together with Tim Krüger he showed that the actual assembly of ribosome subunits, i.e. the association of ribosomal proteins with pre-rRNA, is spatially separate from the transcription sites and occurs in the granular component. Similar localization studies of other nucleolar protein will be an important complement in defining the pathway of ribosome assembly.
Five important publications
Scheer, U. and K.M. Rose (1984): Localization of RNA polymerase I in interphase cells and mitotic chromosomes by light and electron microscopic immunocytochemistry. Proc. Natl. Acad. Sci. USA 81: 1431-1435.
Scheer, U., H. Hinssen, W.W. Franke and B.M. Jockusch (1984): Microinjection of actin-binding proteins and actin antibodies demonstrates involvement of nuclear actin in transcription of lampbrush chromosomes. Cell 39: 111-122.
Krüger, T., H. Zentgraf and U. Scheer (2007): Intranucleolar sites of ribosome biogenesis defined by the localization of early binding ribosomal proteins. J. Cell Biol. 177: 573-578.
Vollmar, F., C. Hacker, R.-P. Zahedi, A. Sickmann, A. Ewald, U. Scheer and M.-C. Dabauvalle (2009): Assembly of nuclear pore complexes mediated by major vault protein. J. Cell Sci. 122:780-786.
Krüger, T. and U. Scheer (2010): p53 localizes to intranucleolar regions distinct from the ribosome production compartments. J. Cell Sci. 123:1203-1208.