The amplified genomic MCP-2 fragment was used to isolate an MCP-2 cosmid from which the gene sequence was determined.
The sequence AAGTGTAATTTTTTGAGTTTCTTTT , which is directly in the intronic hypersensitive area of IFN-gamma , is 83 % homologous to a nearly identical sequence in the 5 ' flanking region of the interleukin 2 gene.
The interferon-gamma gene is highly conserved and changes in IFN-gamma expression are probably due to the influence of regulatory factors on gene transcription , rather than gene polymorphisms.
These effects were not mediated by nitric oxide (NO) , since IFN-gamma failed to induce nitric oxide synthase and NO production.