Direct regulation of the Nrarp gene promoter by the Notch signaling pathway.
Nrarp encodes for an evolutionarily conserved small ankyrin repeat-containing protein that functions as a negative regulator of Notch signaling. Interestingly, increased Nrarp transcription was observed following induction of Notch signaling, suggesting the existence of a negative feedback loop. We show here that both mouse and human promoter regions of Nrarp share two conserved regions located approximately 2 and approximately 3 kb upstream of the transcription start site each containing a perfect putative binding site for the Notch-dependent transcription factor Su(H). A 4.4 kb genomic fragment of the mouse Nrarp locus containing those conserved regions and fused to a luciferase reporter gene showed basal promoter activity in 293T cells and this activity was strongly increased by the intracellular domain of Notch, NICD. NICD-dependent stimulation was attenuated by a dominant negative mutant of Su(H), Su(H)DBM, and was not observed in Su(H)-deficient cells (OT-11). Promoter bashing and gel shift assays revealed that the most distal putative Su(H) binding site located within the -3 kb conserved element plays a crucial role in this induction. Collectively, these results provide definitive support for direct regulation of the Nrarp gene by the Notch pathway.
Laboratoire d'Embryologie Moléculaire, Université Libre de Bruxelles, Institut de Biologie et de Médecine Moléculaires, rue des Profs. Jeener et Brachet 12, B-6041 Gosselies, Belgium.
Pierre
P
Pirot
Leo A
LA
van Grunsven
Jean-Christophe
JC
Marine
Danny
D
Huylebroeck
Eric J
EJ
Bellefroid
D000818:Animals; D001483:Base Sequence; D005786:Gene Expression Regulation / Q000502:physiology*; D017930:Genes, Reporter; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins / Q000378:metabolism*; D051379:Mice; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D011506:Proteins / Q000235:genetics* / Q000378:metabolism; D051880:Receptors, Notch; D015398:Signal Transduction / Q000502:physiology*; D024363:Transcription Initiation Site
D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; C499040:Nrarp protein, mouse; D011506:Proteins; D051880:Receptors, Notch