ALLELE-SPECIFIC EXPRESSION OF THE PSP GENE IN THE MOUSE SUBLINGUAL GLANDS

There are two known alleles of the mouse parotid secretory protein (PS P) gene: Psp(a) and Psp(b). Psp(a) is carried by DBA/2J mice and Psp(b ) is carried by C57BL/6J mice. Eighty-eight mice derived from a F-1(C5 7BL/6J x DBA/2J) to DBA/2J backcross were analysed for PSP mRNA expres sion in the sublingual glands. Expression was found in heterozygous mi ce only. This indicates that only Psp(b) is expressed in this tissue. Furthermore, it maps the allele-specific sublingual gland determinant within 3.4 cM of Psp. Previous analysis of Psp(b) identified an enhanc er-like region in position -4.6 to -3.1 kb that was necessary for tran sgene expression in the sublingual glands. Here it is shown that the c orresponding region in Psp(a) enhances transgene expression in the sub lingual glands as efficiently. The implications for regulation of PSP mRNA expression in the sublingual glands are discussed.