The proposed research is an attempt to understand the molecular mechanisms that regulate the transcription of specific gene sets in time and space in animal development. To achieve this goal it will be necessary to trace the regulatory hierarchy that connects the activation of tissue specific structural genes to the moment of fertilization. The sea urchin embryo will be employed as an experimental system. Regulatory proteins that create and maintain a histospecific program of gene transcription in development will be purified and their genes cloned and characterized. Specifically, Dr. Calzone will purify and clone the gene for sequence specific DNA binding proteins that are essential to control a lineage specific program of differential gene transcription in the early sea urchin embryo. He will identify the essential nucleotides in the site of binding of key spatial control factors of a differentially transcribed gene. He will also describe the molecular mechanisms by which two recently identified negatively acting factors that regulate lineage specific transcription in the sea urchin embryo inhibit the effect of positive acting factors on transcription initiation. %%% An understanding of the molecular mechanisms by which specific gene sets are selected for differential transcription in time and space in the early embryo is essential for an understanding of how the fertilized egg develops into a multicellular adult organism.
