The mouse gastrin gene has three exons totalling 460 bp and a deduced preprogastrin of 101 amino acids. The sequence of murine gastrin-34 is 94% identical to rat gastrin-34 and 76% identical to human gastrin-34. At Arg⁷⁹, mouse progastrin has a unique cleavage site that might allow species-specific synthesis of gastrin-13. Northern analysis and RT-PCR demonstrated that gastrin gene transcripts are abundant in mouse stomach and duodenum and present at low levels in brain, ovary and pancreas, similar to the pattern described for other mammals. The gastrin gene was mapped to the distal region of mouse chromosome 11.