An octamer-binding site is crucial for the activity of an enhancer active at the embryonic met-/mesencephalic junction.
An enhancer sequence found in the Protease Nexin-1 (PN-1) gene was shown to drive lacZ expression specifically at the met-/mesencephalic junction in transgenic mouse embryos. A functional study of this enhancer has been performed to better understand the mechanisms regulating isthmic gene expression. An octamer-binding site for POU domain factors was found to be crucial for the activity of the enhancer in vivo. Comparative expression studies of POU domain factors, electrophoretic mobility shift assays and transient transfection experiments, strongly suggest that Brn-1/-2 regulate the enhancer activity in vivo. In addition, in vitro experiments indicated that FGF-8 was required for the maintenance of the enhancer activity, but not for the synthesis of Bn-1/-2. The data represents the first functional evidence for a role of POU factors in the regulation of met-/mesencephalic gene expression. It also implies that at least two regulatory pathways, namely the FGF-8 signaling and the octamer-binding site pathway, synergistically interact to control the PN-1 enhancer activity in vivo.
Mihailescu
D
D
Friedrich Miescher Institute, Basel, Switzerland.
Küry
P
P
Monard
D
D
D016564:Amyloid beta-Protein Precursor; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism; D002490:Central Nervous System / Q000196:embryology / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D015252:Deoxyribonucleases, Type II Site-Specific / Q000235:genetics / Q000378:metabolism; D004742:Enhancer Elements, Genetic; D005260:Female; D051524:Fibroblast Growth Factor 8; D005346:Fibroblast Growth Factors / Q000235:genetics / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D018398:Homeodomain Proteins; D051863:Host Cell Factor C1; D008297:Male; D008636:Mesencephalon / Q000196:embryology* / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D008815:Mice, Inbred Strains; D008822:Mice, Transgenic; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins; D009479:Neuropeptides / Q000235:genetics / Q000378:metabolism; D050811:Octamer Transcription Factor-1; D050809:POU Domain Factors; D011401:Promoter Regions, Genetic; D058255:Protease Nexins; D051381:Rats; D011956:Receptors, Cell Surface; D012045:Regulatory Sequences, Nucleic Acid; D015398:Signal Transduction; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D001616:beta-Galactosidase / Q000235:genetics / Q000378:metabolism
D016564:Amyloid beta-Protein Precursor; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; C496457:Fgf8 protein, mouse; C496458:Fgf8 protein, rat; C497693:Hcfc1 protein, mouse; D018398:Homeodomain Proteins; D051863:Host Cell Factor C1; D009419:Nerve Tissue Proteins; D009479:Neuropeptides; D050811:Octamer Transcription Factor-1; D050809:POU Domain Factors; C494166:Pou2f1 protein, mouse; C494168:Pou2f1 protein, rat; C484088:Pou3f4 protein, rat; D058255:Protease Nexins; D011956:Receptors, Cell Surface; D015534:Trans-Activators; D014157:Transcription Factors; C085076:transcription factor Brn-2; C074067:Pou3f4 protein, mouse; C074065:Pou3f3 protein, mouse; D051524:Fibroblast Growth Factor 8; D005346:Fibroblast Growth Factors; D004247:DNA; C024388:CTGCAG-specific type II deoxyribonucleases; D015252:Deoxyribonucleases, Type II Site-Specific; C067488:GTMKAC-specific type II deoxyribonucleases; D001616:beta-Galactosidase