Induction of Arylhydrocarbon Receptor Expression in Embryoblast Cells of Rabbit Preimplantation Blastocysts upon Degeneration of Rauber's Polar Trophoblast

• Published in: Toxicology and applied pharmacology 1999-06, Vol.157 (2), p.125-133
• Main Authors: Tscheudschilsuren, G., Küchenhoff, A., Klonisch, T., Tetens, F., Fischer, B.
• Format: Article
• Language: English
• Subjects: AhR nuclear translocator (ARNT); Animals; Aryl Hydrocarbon Receptor Nuclear Translocator; arylhydrocarbon receptor (AhR); Biological and medical sciences; Blastocyst - chemistry; Blastocyst - cytology; Blastocyst - metabolism; Blotting, Western; Cytoplasm - chemistry; Cytoplasm - metabolism; DNA-Binding Proteins; Embryonic Development; Environmental pollutants toxicology; Female; Gene Expression Regulation, Developmental; General aspects; Immunohistochemistry; In Situ Hybridization; Medical sciences; Pregnancy; preimplantation embryos; rabbit; Rabbits; Rauber's polar trophoblast; Receptors, Aryl Hydrocarbon - analysis; Receptors, Aryl Hydrocarbon - genetics; Receptors, Aryl Hydrocarbon - metabolism; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger - metabolism; Sequence Homology, Nucleic Acid; Toxicology; Transcription Factors - genetics; Trophoblasts - cytology; Trophoblasts - metabolism; Trophoblasts - physiology
• ISSN: 0041-008X; 1096-0333
• DOI: 10.1006/taap.1999.8667

The arylhydrocarbon receptor (AhR) is a ligand-activated transcription factor and mediates carcinogenic, teratogenic, and toxic effects of xenobiotics such as dioxin and coplanar polychlorinated biphenyls. The AhR nuclear translocator (ARNT) is involved in AhR signal transduction. We have analyzed the expression of AhR and ARNT mRNA and AhR protein in Day 3 pc (postcoitum) rabbit morulae and Days 4 and 6 pc blastocysts using RT–PCR, nested PCR, whole mount in situ hybridization, and whole mount immunohistochemistry with subsequent confocal laser scanning analysis. AhR and ARNT transcripts were detected in all stages investigated, indicating coexpression of both transcription factors. AhR protein was localized in the cytoplasm. It was detected in Day 3 pc morulae and in blastocysts. In Day 4 pc blastocysts, only trophoblast cells but not embryoblast cells were immunopositive. However, at Day 6 pc, the embryoblast cells also expressed AhR protein and this expression was correlated with the degeneration of Rauber's trophoblast layer.