Abstract: A family of fatty acid transport proteins (FATPS) mediate transport of long chain fatty acids (LCFAs) across cell membranes into cells. These proteins exhibit different expression patterns among the organs of mammals. Nucleic acids encoding FATPs of this family, vectors comprising these nucleic acids, as well as the production of FATP proteins in host cells are described. Also described are methods to test FATPs for fatty acid transport function, and methods to identify inhibitors or enhancers of transport function. The altering of LCFA uptake by administering to the mammal an inhibitor or enhancer of FATP transport function of a FATP in the small intestine can decrease or increase calories available as fats, and can decrease or increase circulating fatty acids. The organ specificity of FATP distribution can be exploited in methods to direct drugs, diagnostic indicators and so forth to an organ such as the heart.

Abstract: A polynucleotide encoding chitin synthase (CHS1), an enzyme essential for cell wall synthesis and yeast cell growth, is provided. A maltose responsive promoter (MRP) isolated using the promoter library of the invention is also described.The present invention also provides a vector for isolation of a eukaryotic regulatory polynucleotide, i.e., promoter. The vector is useful in the method of the invention which comprises identifying a eukaryotic regulatory polynucleotide, i.e., promoter region, by complementing the growth of an auxotrophic host cell containing the vector of the invention, which includes a promoter region operably linked to a promoterless auxotrophic gene. The vector is introduced into the host cell chromosome by targeted integration. Also provided is a library containing host cells having the vector of the invention integrated in the chromosome of the host cell.