Fig. 2.

Structural features of the 5′-flanking region of the human Phox2a gene. A, Schematic representation of the PstI–PstI region showing the relevant restriction sites. The striped boxindicates the DNA sequence specifying the 5′ UTR of the mRNA; theblack region corresponds to the first part of the coding sequence. The arrow indicates the transcription start site. B, Sequence of thePstI–NcoI fragment. The positions are numbered from the transcription start site (indicated by thearrow), as defined by primer extension. The nucleotides in bold correspond to the human Phox2a coding sequence; the shaded region indicates the DNA sequence specifying the 5′ UTR of the mRNA, and the underlined sequencecorresponds to the primer used in the primer extension experiments. The putative TATA box and DNA binding sites for Sp1 and homeodomain transcription factors (hbs, homeodomain binding site) are boxed. The relevant restriction sites are indicated, and their sequences are underlined.