BIOTEC - Biotechnology Center TU Dresden

We are interested in exploiting the mechanisms that control self- renewal and differentiation of mouse embryonic stem cells. These cells originate from the Inner Cell Mass (ICM) of the blastocyst and give rise to all tissues of the embryo including the germline. ES cells are a powerful experimental system to understand the mechanisms that underlie developmental processes.

Embryonic stem cells can differentiate into all 3 germ layers in culture. During differentiation the pluripotent ES cells give rise to progenitor cells that in their turn give rise to terminally differentiated cells. The process of differentiation is guided by the various factors that are added to the culture media and is not yet well understood. It is important to understand this process in order to guide and control it. For this reason we have developed (and continue to develop) various genetic experimental tools. One approach is to conditionally immortalize using tetracycline controlled SV40 large T-Antigen the various cell types that arise during ES cell differentiation. The expression of Large T-Antigen is induced during differentiation followed by cellular cloning. During the induction period the cells proliferate. After ending the induction the cells can be terminally differentiated and characterized with the help of existing markers. The goal is to expand homogenous populations of cells that undergo differentiation and compare their expression profile and epigenetic status.

In other words, we have developed a system that enables conditional immortalization of cell populations that arise during ES cell differentiation. This technical advance opens a door to new mechanistic studies on gene expression hierarchies in differentiation.

• Differentiation of ES cells using lineage selection. The goal is to achieve a homogenous population of progenitors or differentiated cells.

• Analyze the gene expression profile and the chromatin status of the conditionally immortalized progenitors.

• Construction of a tetracycline inducible cDNA library. Screening of the library in ES cell reporter lines and identify candidate genes that drive differentiation.

You can find the complete list of publications (with web links) here.

Anastassiadis, K., Rostovskaya, M., Lubitz, S., Weidlich, S. and Stewart, A. F. (2010). "Precise conditional immortalization of mouse cells using tetracycline-regulated SV40 large T-antigen." Genesis 48: 220-32.

Kranz, A., Fu, J., Duerschke, K., Weidlich, S., Naumann, R., Stewart, A. F. and Anastassiadis, K. (2010). "An improved Flp deleter mouse in C57Bl/6 based on Flpo recombinase." Genesis.

Anastassiadis, K., Fu, J., Patsch, C., Hu, S., Weidlich, S., Duerschke, K., Buchholz, F., Edenhofer, F. and Stewart, A. F. (2009). "Dre recombinase, like Cre, is a highly efficient site-specific recombinase in E. coli, mammalian cells and mice." Dis Model Mech 2: 508-15.

Glaser, S., Lubitz, S., Loveland, K. L., Ohbo, K., Robb, L., Schwenk, F., Seibler, J., Roellig, D., Kranz, A., Anastassiadis, K. and Stewart, A. F. (2009). "The histone 3 lysine 4 methyltransferase, Mll2, is only required briefly in development and spermatogenesis." Epigenetics Chromatin 2: 5.

Lubitz, S., Glaser, S., Schaft, J., Stewart, A. F. and Anastassiadis, K. (2007). "Increased apoptosis and skewed differentiation in mouse embryonic stem cells lacking the histone methyltransferase Mll2." Mol Biol Cell 18: 2356-66.

Glaser, S., Schaft, J., Lubitz, S., Vintersten, K., van der Hoeven, F., Tufteland, K. R., Aasland, R., Anastassiadis, K., Ang, S. L. and Stewart, A. F. (2006). "Multiple epigenetic maintenance factors implicated by the loss of Mll2 in mouse development." Development 133: 1423-32.

Schnutgen, F., Stewart, A. F., von Melchner, H. and Anastassiadis, K. (2006). "Engineering embryonic stem cells with recombinase systems." Methods Enzymol 420: 100-36.

Glaser, S., Anastassiadis, K. and Stewart, A. F. (2005). "Current issues in mouse genome engineering." Nat Genet 37: 1187-93.

All current group members are listed on the Staff Page.

You can learn more about the group members by visiting their personal websites on our group page.