Cloning of Decidual Prolactin from Rhesus Macaque1

Rhesus monkey (Macaca mulatta) decidual prolactin cDNA was cloned and sequenced. The first 210 bp of the monkey sequence is not contiguous to the human pituitary prolactin transcription initiation site. Reverse transcription-polymerase chain reaction (RT-PCR) and Southern analysis confirmed that this 5'-extended prolactin transcript is present in monkey decidua but not in pituitary. Isolation and sequencing of a partial genomic monkey prolactin clone verified the nucleotide changes found in the rhesus cDNA. Comparison of the rhesus decidual prolactin cDNA to the human pituitary cDNA revealed more than 97% homology between the two. These data indicate that monkey prolactin mRNA from the decidualized endometrium of pregnancy contains unique 5' sequence not present in pituitary prolactin mRNA, suggesting the use of an alternative start site. Thus it is likely that the decidua uses promoter and regulatory regions different from those reported for pituitary prolactin.