The structure and complete nucleotide sequence of the murine gene encoding interleukin-1 beta converting enzyme (ICE)

Abstract

Interleukin-1 beta (IL-1 beta) converting enzyme (ICE) processes the precursor of the cytokine IL-1 beta to a mature, biologically active form in monocytes and macrophages. To further understand the role of ICE in regulating IL-1 beta-mediated biological functions, we have isolated several genomic clones encoding the full-length murine ICE gene. Southern blot comparison of murine genomic DNA and the clones indicates that ICE is a compact, single-copy gene 8616 bp in size. We sequenced the entire gene as well as 1.0-kb segment upstream of the coding region and determined that the gene consists of 10 exons whose organization parallels the functional organization of the ICE proenzyme in that the prodomain and p20 and p10 subunits of ICE are encoded by three clusters of exons. Two initiation sites, 37 and 32 nucleotides upstream of the initiator methionine, were identified by primer extension analysis. The 5' region of the ICE gene lacks a TATA box, a CAAT box, and SP1 sites. However, the presence of a completely conserved 14-bp sequence spanning the transcription initiation site of both the murine and the human ICE genes suggests that this sequence plays a role in transcription.