Characterization of the goat lactoferrin cDNA: assignment of the relevant locus to bovine U12 synteny group

Lactoferrin (LTF), which is the major iron-binding protein in milk and physiological fluids, belongs to the transferrin family. We report here the sequence of a caprine LTF cDNA, 2411 bp in length, encoding the pre-protein (709 amino acid residues). Sequence comparisons reveal that structural features, including iron-binding sites, cysteine residues involved in disulphide bonds are remarkably conserved between LTF proteins from various species. Of the 5 potential glycosylation sites identified, only one site appears to be conserved between artiodactyls, rodents and humans. Using a somatic cell hybrid panel, the LTF locus was assigned to the bovine U12 syntenic group. This assignment and the localization of the LTF gene on bovine chromosome 22 (BTA 22) by Schwerin et al. (1) using fluorescent in situ hybridization achieves an additional analogy between a synteny group and a chromosome in cattle. Since serum transferrin (STF) had been previously mapped on BTA 1, in cattle LTF and STF loci are not localized on the same chromosome, conversely to the situation observed in humans (HSA 3) and mice (MMU 9).