Regional specification describes a process by which specific characteristics and function are ascribed to different parts of the gastrointestinal tract. Bone morphogenetic protein (BMP) signaling in necessary for proper patterning of the colon in model organisms and in pluripotent stem cell derived human colonic organoids (HCOs). Using HCOs as a model system, we propose to examine how BMP signaling establishes the genomic landscape of the developing colon. We hypothesize that during human colonic patterning, bone morphogenetic proteins (BMPs) induce the expression of epithelial SATB2 and mesenchymal BCOR, GATA2 and GATA3 that are required to establish a genomic environment that supports the transcription of colonic mRNAs and represses the expression of small intestinal mRNAs. Our proposal consists of 2 specific aims. Aim 1: Determine the molecular mechanisms through which BMP patterns colonic progenitors from human pluripotent stem cells. Aim 2: Determine if SATB2 mediates the patterning of the colonic epithelium. Success in the proposed studies will provide unique mechanistic insights into colonic differentiation as well as identify novel therapeutic targets to treat ulcerative colitis and colitis associated cancers which are known to display patterning defects.