Genetic mapping of the galanin-GMAP (Galn) gene to mouse chromosome 19

The galanin-GMAP gene (Galn) encodes preprogalanin, which is enzymatically cleaved into the peptides galanin and galanin message-associated peptide (GMAP; Fig. 1a; Roekaeus 1994). Galanin mRNA and peptide have been detected widely in the central and peripheral nervous systems, in endocrine tissues such as the hypothalamus, anterior pituitary, pancreas, adrenal, thyroid and parathyroid glands, and in developing bone (Roekaeus 1994; Xu et al. 1996). Physiological studies suggest that galanin modulates neuroendocrine systems by affecting satiety, the development of prolactinomas, potentiating growth hormone and gonadotropin release, and inhibition of insulin release (Roekaeus 1994; Bedecs et al. 1995; Wynick et al. 1993). However, a precise physiological role for the galanin and GMAP peptides has yet to be determined, despite high conservation of galanin across species (Kofler et al. 1996). As the first step in a genetic approach to understanding the Galn gene function, we have mapped the mouse Galn gene to proximal Chromosome (Chr) 19 by interspecific backcross and recombinant inbred strain analyses. The region of synteny between this region and human Chr 11q13, where human GALN has been localized (Evans et al. 1993; Guida et al. in preparation), suggests the likely location of mouse homologs of a series of human endocrine disease loci. Southern analyses of restriction digests of mouse DNA with a Galn cDNA probe identified an MspI restriction fragment length polymorphism (RFLP) between different recombinant inbred (RI) strains of mice.