The genome of each cell within an organism contains hereditary information. Among other features, the genome contains genes – DNA sequences that specify the genetic code (encode) for functional products such as proteins. The product of a gene is produced when the gene is turned on (expressed). The process of turning certain genes on or off is governed by regulatory proteins called transcription factors (TFs). While cells of different tissues within an organism contain the same genome, their function may be different due to the fact that they express different genes. While in simpler organisms gene expression is regulated by individual TFs, in more complex organisms such as mammals, several TFs may work together to control the expression of a gene. Many complex diseases such as cancer are at least partially due to improper expression of certain genes. Understanding how gene expression is regulated in an organism, including identifying what TFs work together to regulate particular genes, is instrumental to understanding the biology of numerous health conditions. Olena Morozova is working as part of a large research project aimed at identifying genetic networks governing development. Using the mouse as a model system to study the regulation of gene expression, she is focusing on how different TFs interact to regulate the development of mouse pancreas, heart, and liver, and how these interactions can be used to identify master regulators and the main control nodes in the development of these organs. Overall, this project will provide invaluable insights into mammalian gene regulation and will ultimately help to understand the biology of diseases resulting from errors in the regulation of gene expression. The identified TFs that work together with many other TFs are potentially useful targets for effective disease therapy.