Molecular studies on interleukin-1 alpha.

When rabbit alveolar macrophages were treated with phorbol-12-myristate-13-acetate (PMA) and lipopolysaccharide (LPS), the synthesis of interleukin-1 (IL-1), as well as tumor necrosis factor (TNF), was greatly increased. These inducible cytokines were subjected to cloning by the differential colony hybridization method and the subsequent mRNA hybridization-translation assay. Cloned rabbit IL-1 cDNA was disclosed to encode the sequence of the counterpart of the mouse IL-1 alpha. This cDNA was used as a hybridization probe to screen a human cDNA library which was constructed from induced HL-60 cells, a human promyelocytic leukemia cell line. Isolated human IL-1 alpha cDNA was shown to direct the synthesis of a polypeptide with IL-1 activity in E. coli expression system. The chromosomal gene for human IL-1 alpha was isolated and characterized to elucidate the structural organization of this gene. To identify the region that is essential for regulating IL-1 alpha gene expression, various CAT (chloramphenicol acetyltransferase) fusion plasmids were constructed and analysed for their ability to direct CAT synthesis in a transient expression system. The unpublished results obtained in the early stages of these experiments are also presented and discussed in this review.