9407923 Sladek This is a Research Planning Grant. The long term goal of this research is to determine the origins of nuclear receptors and thereby shed light on how this important family of transcription factors enables a cell to respond to outside stimuli. The short term goal of the planning activities is to characterize and clone from yeast a putative nuclear receptor. There are two specific aims: 1, to purify a factor from Saccharomyces cerevisiae that binds specifically to a known nuclear receptor response element, using conventional and affinity chromatography along with an electrophoretic mobility shift assay to purify sufficient amounts of the protein for partial amino acid sequencing; and 2, to clone the corresponding gene from a S. cerevisiae genomic library, using oligonucleotides derived from the partial amino acid sequence. %%% Transcription factors are DNA-binding proteins which control whether or not specific genes are transcribed (active) or not. Many transcription factors act in response to external "signals" (such as hormones) and represent an important part of the mechanism whereby an organism responds to such "signals" by turning specific genes on or off. This project is based on the hypothesis that there exist, in yeast, transcription factors which are dependent on lipophilic ligands. Such factors exist in higher organisms, and represent those transcription factors which are responsive to certain lipophilic hormones (e.g., steroids) and other lipophilic signalling molecules that control development, differentiation, and hormone-dependent gene expression. The idea that similar factors exist in yeast is based in part on theoretical arguments and in part by preliminary data. If, as is hoped, such factors can be identified in yeast, it will then be possible to use genetic manipulations, which are powerful and well-developed in yeast, to study them further. ***
