This proposal is to study regulation of gene expression by interaction with transcription factor proteins which bind certain specific sequence elements in the DNA. Two classes of transcription factors have been described: AP1 and CREB. In order to bind DNA, the proteins must first dimerize. One of the AP1 proteins, cJUN, can form homodimers and respond to the TRE sequence element, or can form heterodimers with any of three CREB proteins and bind to the CRE sequence element. Each of these complexes has a unique trans- activation potential. All potential dimer complexes will be trans- lated from cDNA clones in reticulocyte lysates, and binding to oligonucleotides of known sequence will be determined by gel retardation analysis. Constructs of a plasmid containing the reporter gene luciferase coupled to the various oligonucleotides will be used to determine transactivation potential at various points in the cell cycle. %%% This proposal is to study proteins which enhance and promote the transcription of DNA, the genetic material. Two kinds of proteins (a total of four) will be used. The proteins contain two interesting structural features: DNA binding regions and "leucine zippers", which allow the proteins to form pairs of identical or different proteins. Each dimer binds to a unique sequence in DNA; the sequences will be determined and compared. The importance of the stage of the cell cycle for one type of dimer or another will be determined using luciferase from firefly tails as a reporter molecule.
