THE GENE FOR THE HUMAN INTERLEUKIN-11 RECEPTOR-ALPHA CHAIN LOCUS IS HIGHLY HOMOLOGOUS TO THE MURINE GENE AND CONTAINS ALTERNATIVELY SPLICEDFIRST EXONS

The gene for the murine interleukin-ll receptor a chain (mIL-11R alpha ) contains two loci (1 and 2), of which locus 2 is restricted to only some mouse strains. Two alternatively spliced exons (la and Ib) encode the 5' untranslated region (5'UTR) of the murine locus 1. We have cha racterized the gene for the human interleukin-ll receptor a chain locu s (hIL-11R alpha), examined its expression by Northern analysis and de termined its chromosomal location by fluorescence in situ hybridizatio n. The presence of exon(s) encoding the 5'UTR and mapping of transcrip tion initiation sites was determined by reverse-transcriptase polymera se chain reaction and 5' rapid amplification of cDNA ends (5'RACE) tec hniques, The human locus spanned 10 kilobasepairs (kb) and consisted o f 14 exons. Two alternatively spliced first exons (la and Ib) encoding the 5'UTR were identified and shared 76 and 73% nucleotide identity w ith murine exons la and Ib. Multiple transcription start sites were de monstrated for human exon la. The promoter regions of both human exons la and Ib did not display a canonical TATA box. A predominant 1.8 kb transcript for the hIL-11R alpha was present in heart, brain, skeletal muscle, lymph nodes, thymus, appendix, pancreas and foetal liver. The hIL-11R alpha gene was localized to chromosome 9p13. In summary, the hIL-11R alpha gene was highly related to locus 1 of the murine gene an d there was no evidence of a second hIL-11R alpha locus. (C) 1997 Else vier Science Ltd.