Organization of the human interleukin-1 receptor antagonist gene IL1HY1

The interleukin (IL)-1 family of proteins plays an important role in inflam matory and defense mechanisms. The recently characterized IL1HY1 cDNA encod es a new member of the IL-1 receptor antagonist family (IL-1ra), In this re port, we describe the complete nucleotide sequence of the human IL1HY1 gene . We sequenced approximately 7600 nucleotides and found four coding exons r anging in size from 55 to 2288 nucleotides. The 5' untranslated region is f ormed by one of two alternatively used exons and one invariably present exo n which also contains the region encoding the first nine amino acids of the protein. IL1HY1 and IL-1ra intron positions are well conserved within the protein-coding region, providing evidence that these genes arose from a dup lication of a primordial IL-1 receptor antagonist gene.