Nucleotide Sequence of the S-Acyl Fatty Acid Synthase Thioesterase Gene and Its Tissue-Specific Expression

S-Acyl fatty acid synthase thioesterase causes the production of short-chain acids in mammary glands and avian uropygial glands. Southern blot analysis indicated that the duck genome probably has a single copy of the thioesterase gene. The thioesterase gene with its flanking regions was cloned in λ Charon 35 and sequenced. This 9-kb gene consists of seven exons which showed complete homology with the cDNA sequence. Within the 1.1-kb 5′-flanking region were a series of six adjacent potential stem-and-loop structures. A search for steroid hormone receptor binding sites revealed no putative binding sites within the 5′-flanking region of this gene. However, putative binding sites for progesterone, glucocorticoid, and estrogen receptors were found within the first intron. Within a 370-bp segment, eight putative binding sites were found, along with both CCAAT and TATA box sequences. The adjacent putative hormone binding sites might play a functional role in the regulation of expression of this gene. Slot blot analysis showed that this gene is highly expressed specifically in the uropygial gland, though transcripts could be detected in testes, kidney, brain, and liver.