Sucrose octaacetate avoidance in nontaster mice is not enhanced by two type-A Prp transgenes from taster mice

The Soa bitter-sensitivity and Prp salivary-protein loci map to distal mous e chromosome six. No recombination has been found between sucrose octaaceta te (SOA)-avoidance phenotype and PRP haplotype in any mouse population. Soa and Prp, therefore, are either very near each other or identical. To asses s the latter possibility, two type-A, proline-rich protein genes (MP2 and M 14), situated similar to 30 kb apart at the Prp locus, were separately tran sferred from an SOA-taster inbred strain (SWR) to an SOA-nontaster inbred s train (FVB). Five MP2-transgenic mice and seven M14-transgenic mice were in sensitive to 1 mM SOA in two-bottle tests, thus retaining the nontaster FVB phenotype. Each transgenic mouse was mated to control FVB mice. Their tran sgene-positive F1 and F2 offspring also were insensitive. Transgene express ion varied among the founder lines, but SWR-like expression levels, higher than background FVB expression levels, were found in submandibular gland ti ssue of adult transgenic mice from two MP2 lines and one M14 line. F3 mice from one of these MP2 lines were mated to F2 mice from the M14 line. Nine o ffspring inherited both transgenes. All nine were insensitive to 1 mM SOA. These findings indicated that expression of mRNAs for both type-A Prp genes alone or together did not enhance SOA taste sensitivity in nontaster mice.