Structure of the human aldose reductase gene

The structure and sequence of the human gene for aldose reductase (AR) was determined by analysis of cDNA and genomic clones. The AR gene was independently isolated from two different cosmid libraries and the clones were characterized by restriction mapping, Southern blotting, and DNA sequencing. The gene extends over approximately 18 kilobases and consists of 10 exons giving rise to a 1,384 nucleotide mRNA (excluding the poly(A) tail). The human aldose reductase gene codes for a 316-amino acid protein with a molecular mass of 35,858 daltons. The size range for the exons is 82-168 base pairs (bp), whereas that for the introns is 325 to about 7,160 bp. A major site of transcription initiation in liver was mapped to an A residue 31 nucleotides upstream from the A of the ATG initiation codon. The promotor region of the gene contains a TATA (TATTTA) box and a CCAAT box which are located 37 and 104 nucleotides upstream, respectively, from the transcription initiation site. We have found four Alu elements in the AR gene; two are found in intron 1 and one each in intron 4 and intron 9.