Searle Scholar Profile : Joanna K. Wysocka (2007)

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	Joanna K. Wysocka Assistant Professor Department of Chemical and Systems Biology and Department of Developmental Biology Stanford University School of Medicine 269 Campus Drive CCSR Room 3145C Stanford, CA 94305-5174 Phone: 650-736-0672 Email: wysocka@stanford.edu Personal Homepage 2007 Searle Scholar

EPIGENETIC REGULATION OF DIFFERENTIATION AND DEVELOPMENT

The biological question that is driving our research in the long-term is understanding the epigenetic basis of vertebrate development and differentiation. Although each cell of a multicellular organism is a progeny of a single zygote, and shares the same genetic information with every other cell, cells differentiate to specialized forms such as skin, muscle or nervous cells. Thus, new information emerges during development, and is inherited in a way that does not involve changes in DNA sequence. This fascinating process is called epigenesis. Epigenetic changes underlie not only normal, but also pathological development. Abnormal transmission of epigenetic information contributes to human pathology, such as aging, cancer, degenerative diseases, developmental defects and mental retardation.

In the last decade evidence emerged that a substantial portion of epigenetic information is transmitted in a form of chemical modifications of histones and associated DNA. Our research focuses on understanding the mechanistic basis by which covalent histone modifications regulate gene expression patterns during vertebrate development and differentiation. In particular, we are focusing on characterizing enzymatic activities responsible for "writing" the methyl mark on histones, called histone methyltransferases, as well as on downstream effectors, or "readers", which recognize the methyl marks and translate them into specific biological outcomes. Although the recent progress in chromatin field identified many new molecules involved in the regulation of histone methylation, our understanding of role of these proteins in epigenetic regulation of development, particularly vertebrate development, is still in its infancy. The outstanding questions we are trying to address are: How are methylation patterns established? How do methyltransferases connect to the signaling pathways? What are their roles in regulating development and how did they functionally specialize during vertebrate evolution?

A second major area of our interest involves chromatin regulation in embryonic stem cells (ESCs) and molecular basis of pluripotency. ESCs share with the early embryo the potential to produce every type of cell in the human body. This rare biological property is known as pluripotency. Pluripotency is a unique epigenetic state, in that ESCs can self-renew, while retaining the potential for multilineage differentiation. Our goal is to link the transcription factors that specify ESC identity with chromatin modifying machinery that is essential for mediating this specification, and to identify major players in recognizing modified histone tails in human and mouse embryonic stem cells.