This proposal is to request support for a Keystone Symposia meeting entitled Dynamics of Eukaryotic Transcription during Development, organized by Karen Adelman and Marc Timmers, which will be held in Big Sky, Montana from April 7 - 12, 2010. Gene expression in eukaryotes is regulated primarily at the level of transcription. Although much is known about the basic building blocks required to recruit RNA polymerase II to a gene promoter and establish a pre-initiation complex, recent data reveals that a great deal of regulation occurs during transcription elongation, and involves dynamic interactions between the transcription machinery and chromatin structure. This symposium will cover fundamental mechanisms of gene expression, and the ways in which it can be regulated and disregulated during cellular differentiation, development and proliferation. Based on the increasing level of interest in the interplay between transcription, chromatin, and epigenetics in maintaining and controlling pluripotency in embryonic stem cells, we have chosen to make this one of the focal points of the meeting. It has become clear that a real understanding of chromatin and gene expression changes governing cell fate and proliferation will require combining knowledge derived from a breadth of techniques and disciplines. With this in mind, a defining feature of this meeting is that it strives to bring together researchers who might not otherwise interact, and involves biochemists, cell biologists, developmental biologists, oncologists and those doing genomic-scale and bioinformatic research, with a common focus on how patterns of gene expression are established. In order to provide a platform for the most promising young researchers, a special afternoon workshop is planned for topics deemed "new and noteworthy". Moreover, with a desire to present fresh perspectives, we have chosen to place an emphasis on presenting new and emerging techniques to study in vivo dynamics, such as live-cell imaging of protein interactions and transcription, and methods for evaluating nuclear structure and organization.