Hif1a exon I.2 and flanking regions. The sequence of exon I.2 is in bold, repetitive elements and restriction enzyme recognition sites are underlined, and putative transcription factor consensus binding sites are double underlined. The transcription initiation sites mapped by primer extension and mung bean nuclease protection (see Fig 4) are indicated by filled arrows and the start of intron 1 by an open arrow. The predicted translation initiation codon and the first 12 amino acids of the exon I.2 isoform are indicated. The location of the oligonucleotide mHIFpex2 is depicted with a line over the sequence.