THE HUMAN ETS1 GENE - GENOMIC STRUCTURE, PROMOTER CHARACTERIZATION AND ALTERNATIVE SPLICING

Genomic clones encompassing the human ETS1 gene were isolated and utilized to define its molecular organization. This gene consists of eight exons spanning over 60 kb. The 5' end of the human ETS1 gene was subcloned and characterized. S1 nuclease, primer extension and RNAase protection analyses of human mRNAs showed multiple transcription initiation sites. DNA sequence analysis indicated a high G + C content in the promoter region and the absence of either a 'TATA' box or a 'CAAT' box. Six consensus recognition sequences for the transcription factor SP1, two AP1 consensus sequences and one consensus AP2 recognition sequence were identified, as well as two GC elements with dyad symmetry. A palindromic region similar to the serum response element of the c-fos gene and two octamer consensus recognition sequences were located upstream of the promoter region. A series of promoter deletion constructs positioned upstream from the bacterial chloramphenicol acetyl transferase gene were transfected into HeLa cells and their functional promoter activity assayed. The deletion constructs identified the 5' boundary for maximum promoter activity at 486 bp upstream of the first initiation site and suggest possible positive and negative regulatory regions. Polymerase chain reaction analysis of ETS1 cDNA identified several amplified products, indicating alternative splicing. In addition to the presence of mRNA products lacking exon VII, products lacking exon IV, as well as ones lacking both exons IV and VII, were found.