RAT PROLACTIN-LIKE PROTEIN-A PARTIAL GENE AND PROMOTER STRUCTURE - PROMOTER ACTIVITY IN PLACENTAL AND PITUITARY-CELLS

Rat prolactin-like protein A (rPLP-A) is a member of a rapidly expandi ng family of prolactin-related proteins that are expressed during preg nancy by the rat placenta according to specific developmental patterns . Although the factors involved in the pituitary-specific expression o f the prolactin and growth hormone genes themselves have been extensiv ely studied, essentially nothing is known of the factors responsible f or the placental expression of these new family members. In this paper we describe the isolation of rPLP-A genomic clones, analyze a portion of the 5' flanking sequence of this gene and use the recently describ ed rat choriocarcinoma cell line, Rcho, in transient transfection stud ies to show that a 975 base-pair (bp) fragment of 5' flanking sequence is sufficient to specify placental expression of the rPLP-A gene.