Figure 1. Comparative sequence analysis.

Nucleotide sequences of the 5′-flanking regions in rat, mouse and human orthologues of the glucagon gene were aligned using the program DIALIGN [14] and scanned for potential transcription factor-binding sites using weight matrix description of binding sites and the program MatInspector Professional. Upper-case letters denote aligned regions. The positions of a novel Foxa/forkhead site (the Foxa site A), which is located downstream of the G1 element, and the previously described Foxa sites in the G1 and G2 elements as well as the TATA box and CREs are illustrated. Note that the Foxa/forkhead site in the G2 element is detected only in rodent sequences, not in human sequences, and that the nucleotides at Foxa sites A–C are identical between the rat and mouse sequences. Nucleotides matching the Foxa/forkhead consensus recognition sequence (VAWTRTTKRYTY; V=A, C or G; W=A or T; R=A or G; K=G or T; Y=C or T) are highlighted in boldface. The sequences are numbered relative to the transcription start site (+1). G1–G3 regulatory regions are marked by overbars above the sequence. The mouse sequence has been deposited in GenBank® database under the accession number AF356593. ATF, activating transcription factor.