DIFFERENTIAL EXPRESSION OF THE TEF FAMILY OF TRANSCRIPTION FACTORS INTHE MURINE PLACENTA AND DURING DIFFERENTIATION OF PRIMARY HUMAN TROPHOBLASTS IN-VITRO

We describe the molecular cloning of murine (m) Transcriptional Enhanc er Factor (TEF)-5 belonging to the TEF family of transcription factors . We show that mTEF-5 is specifically expressed in trophoblast giant c ells and other extra-embryonic structures at early stages of developme nt. At later stages, mTEF-5 is specifically expressed in the labyrinth ine region of the placenta and in several embryonic tissues. We furthe r show that the other mTEFs are differentially expressed in extraembry onic structures and in the mature placenta, Interestingly, human (h)TE F-5 is specifically expressed in the differentiated syncytiotrophoblas t of the human term placenta and its expression is upregulated during the differentiation of cytotrophoblasts to syncytiotrophoblast in vitr o, whereas that of hTEF-1 is down-regulated, Together with previous re sults describing hTEF-binding sites in the human placental lactogen-B gene enhancer, these novel observations support a role for hTEF-5 in t he regulation of this gene. We further propose that the hTEF factors m ay play a more general role in placental gene regulation and developme nt. Dev. Dyn. 1998;212:423-436. (C) 1998 Wiley-Liss,Inc.