Genomic structure of the human ATR gene. The sizes of exons and introns are represented by proportionaly sized dark boxes and solid lines, respectively. The 5' and 3' untranslated regions are indicated by light boxes in the gene and mRNA structure. The GenBank accession number corresponding to the ATR gene contig, the mRNA and the protein are indicated below the nucleotide and protein sequence. The domains involved in the ATR protein activity are illustrated in the protein structure. All polymorphisms are indicated in open boxes while amino acid nomenclature is also represented.