Detection of the mRNA to placental alkaline phosphatase by in vitro translation and immunoprecipitation.

RNA prepared from human placental syncytiotrophoblast tissue was analysed by in vitro translation and immunoprecipitation. The major polypeptide synthesized from syncytiotrophoblast mRNA was human placental lactogen, accounting for 15-20 per cent of the translated polypeptides. Immunoprecipitation using antibodies to placental alkaline phosphatase (PLAP) specifically precipitated polypeptides of 56 kD and 58 kD. The possible relationship between these polypeptides and those of placental microvillus PLAP is discussed.