Transcriptional Regulation and Role of a Transcription Factor Involved in Gut Development.

University Of Missouri-Kansas City, Columbia MO

Investigators

Abstract

0090201 Livingston A crucial step during embryonic development is the formation of the three tissue layers that make up the basic animal body plan: ectoderm, endoderm and mesoderm. The Livingston laboratory is investigating how the endoderm, which gives rise to the digestive system and associated organs, is formed during development. Specifically, Dr. Livingston studies how endoderm-specific genes are regulated at the level of transcription using sea urchin embryos as a model system. This involve studying both the segments of DNA involved in controlling gene expression and the proteins that bind to these DNA sequences and regulate transcription by RNA polymerase. Spfkhl, a gene that encodes a winged helix transcription factor that is centrally located in the cascade of gene regulation leading to endoderm differentiation, will be utilized as a starting point. In Specific Aim 1, the Livingston laboratory will examine the cis-regulatory sequences that control Spfkhl expression using powerful techniques that have been developed in sea urchins for studying gene regulation using reporter constructs. In Specific Aim 2, the Livingston laboratory will examine the role of the Spfkhl protein in endoderm formation. This will be accomplished using injection of either full length mRNA encoding Spfkhl to assess the effects of overexpression of this gene on endoderm development, or dominant-negative forms of Spfkhl mRNA, which will assess the effects of the loss of Spfkhl function on endoderm development. In Specific Aim 3, the Livingston laboratory will isolate and characterize genes that are regulated by Spfkhl, and will begin to analyze the function of these genes in endoderm development. These studies should allow the Livingston laboratory to learn more about the interactions of transcription factors on an endoderm-specific gene regulatory region, including both positive and negative regulators and the importance of context on the role of these factors. Such studies, when compared to studies on other endodermal genes in a variety of organisms, will allow Dr. Livingston to begin to dissect the conserved mechanisms in endodermal gene expression. Identification of novel regulators of this gene, and targets of this gene, will identify new molecules that play a role in endoderm development. These can then be studied both in the sea urchin model system as well as in other species.