Johnson, Caitlin M.2014-01-282014-01-282013-12https://hdl.handle.net/11299/162360University of Minnesota M.S. thesis. December 2013. Major: Stem Cell Biology. Advisor: Susan Keirstead, Randy S. Daughters. 1 computer file (PDF); v, 50 pages, appendix p. 48-50.As an embryo develops, the heart is the first functional organ to form. There are four cell populations that are the primary contributors to the developing heart during embryogenesis. The populations which comprise the majority of the organ are the primary and secondary heart fields. The primary heart field commits to the cardiac lineage slightly before the secondary heart field in development. During cardiac lineage commitment, cells pass through a series of stages before becoming terminally differentiated. Prior to differentiation, cells express the transcription factor <italic>Oct4<italic> which functions to maintain the pluripotent state of the cell. <italic>Oct4<italic> has been also proposed to play a direct role in early stages of cardiac lineage commitment. We used an <italic>Oct4<italic>-CreER reporter iPS cell line with embryoid body differentiation to determine presence of <italic>Oct4<italic> transcript at a given time to study the cells of primary and secondary heart fields. Use of this system allowed us to separate cells based on <italic>Oct4<italic> expression, and further characterize the gene expression in these populations. We probed for the gene expression patterns of the heart fields to test the role of <italic>Oct4<italic> expression in the individual fields.en-USCardiac lineageEmbryoid bodyHeart fieldiPSOct4Stem cellThesis or Dissertation