A NEW MEMBER OF THE MOUSE PROLACTIN (PRL)-LIKE PROTEIN-C SUBFAMILY, PRL-LIKE PROTEIN-C-ALPHA - STRUCTURE AND EXPRESSION

In this study, we establish the presence of a unique member of the PRL -like protein-C (PLP-C) subfamily in the mouse, PLP-C alpha, character ize its complementary DNA and gene, and map its chromosomal location a nd pattern of expression during pregnancy. Mouse PLP-C alpha encodes f or a 239 amino acid protein and possesses from 69-71% identity with ra t PLP-C, PLP-CV, PLP-D, and PLP-H. Another feature characteristic of P LP-C subfamily members that is also present in mouse PLP-C alpha is a 6-exon/5-intron gene structure including an aromatic domain encoded by exon 3. Southern analysis with mouse and rat PLP-C subfamily probes s uggested the existence of a single mouse PLP-C alpha gene. Mouse PLP-C alpha maps to chromosome 13 along with other members of the mouse PRL family. Expression of mouse PLP-C alpha increases dramatically as ges tation advances and is restricted to spongiotrophoblast and trophoblas t giant cells of the junctional zone. In summary, we have established the presence of a new PLP-C subfamily member in the mouse and demonstr ated its similarity in structure and expression to rat PLP-C subfamily members. This level of conservation between species expands the biolo gical significance of the PLP-C subfamily and provides additional oppo rtunities for genetically evaluating its function.