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DEVELOPMENTAL EXPRESSION OF TWO MEMBERS OF A NEW CLASS OF TRANSCRIPTION FACTORS: II. EXPRESSION OF ARYL HYDROCARBON RECEPTOR NUCLEAR TRANSLOCATOR IN THE C57BL/6N MOUSE EMBRYO
Citation:
Abbott, B. AND M. Probst. DEVELOPMENTAL EXPRESSION OF TWO MEMBERS OF A NEW CLASS OF TRANSCRIPTION FACTORS: II. EXPRESSION OF ARYL HYDROCARBON RECEPTOR NUCLEAR TRANSLOCATOR IN THE C57BL/6N MOUSE EMBRYO. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-95/504, 1995.
Description:
The Aryl hydrocarbon receptor (AhR) is a ligand-activated, transcription factor with a basic region/helix (bHLH) motif. hR has been sequenced and the functional domains defined and there is information on the formation of complexes with other peptides and interactions with DNA, although these areas continue to be investigated. hR mediates many biological effects such as developmental toxicity, including induction of cleft palate and hydronephrosis. his regulatory protein is expressed in embryonic liver and has been immunohistochemically localized in cells of human and mouse secondary palate. he expression of AhR in embryonic tissues and its ability to disrupt development suggests a significant role for this protein in development. he present study examines the pattern of AhR expression in the C57BL/6N mouse embryo from gestation days (GD) 10-16, using in situ hybridization and immunohistochemical analysis. hR mRNA was localized with 35S-RNA antisense riboprobe (cAhl probe, 1.8 Kb amino terminal DNA, C. Bradfield). hR protein was localized with purified monoclonal antibody (RPT-9) raised against the N-terminal peptide sequence. hR MRNA and protein were expressed in GD 10-13 neuroepithelium and as development progressed, the levels in brain decreased. D 10-12 embryos also showed AhR in bronchial arches, heart, somites and liver. hR protein and MRNA in heart were highest at GD 10-11 and decreased with age. n liver, AhR MRNA and protein levels increased and nuclear localization became more pronounced with gestational age. in GD 14-16 embryos levels in liver and adrenal were highest, but AhR was present in ectoderm, bone, and muscle. hR expression was specific for both cell type, organ/tissue, and developmental stage, suggesting that this novel ligand-activated, transcriptional regulator has a role in normal embryonic development.