STRUCTURE AND ANALYSIS OF THE 5' FLANKING REGION OF THE HUMAN INTERLEUKIN-2 GENE

To investigate the structural and functional organization of the human interleukin-2 locus, the nucleotide sequence of 9339 bp of the 5' fla nking region of this gene has been determined. Computer search analysi s reveals five stretches with a high degree of homology between the hu man and mouse 5' flanking sequence, including a very distant 5' region . In this region additional binding sites for potential transcription factors were found that are identical to known regulatory sequences. T he possible roles of these putative regulatory elements in the interle ukin-2 gene regulation remain to be proven. The 5' end of the sequence contains almost full-length LINE element. LINE consensus open reading frames ORF1 and ORF2 in the reported sequence are interrupted by inse rtions, deletions or in-frame nonsense mutations. Comparative analysis of the ratio of codon changes that result in amino acid replacement t o those that are silent revealed a high silent mutation frequency thro ughout the consensus ORF1 3' end, suggesting that this region is proba bly under selection for protein function.