Abstract: The present invention provides nucleotide sequences encoding human LTC4 synthase or variants thereof, which nucleotide sequences include a human LTC4 synthase genomic clone, and unique fragments thereof. The present invention also provides recombinant plasmids, and cells transformed therewith, including the LTC4 synthase gene sequences. The present invention further provides the chromosomal localization of the human LTC4 synthase gene, and also provides methods for identifying LTC4 synthase gene mutations that correlate with susceptibility to bronchial asthma. Diagnostic methods are also provided, as are methods for identifying LTC4 synthase modulators (i.e., compounds that alter the expression and/or activity of LTC4 synthase). The presents invention also provides functional equivalents of the LTC4 synthases, protein, and also methods of identifying LTC4 synthase inhibitors.

Abstract: An isolated nucleotide sequence encoding human leukotriene C4 synthase or variants of human leukotriene C4 synthase polypeptide, is provided. One embodiment is an isolated DNA sequence (SEQ ID NO.:1) encoding a human leukotriene C4 synthase polypeptide, that has three hydrophobic transmembrane domains. Also described are recombinant cells and plasmids containing the foregoing isolated DNA, preferably linked to a promoter. Isolated leukotriene C4 synthase is provided, having at least three hydrophobic transmembrane domains (SEQ ID NO.:2). Portions of the foregoing isolated human leukotriene C4 synthase polypeptide are also described. Antibodies with selective binding specificity for the polypeptides of the invention also are provided as well as a sensitive method for assay of human leukotriene C4. Methods for producing leukotriene C4 synthase as well as methods for testing for modulators of leukotriene C4 synthase activity are also described.