Cdx regulates Dll1 in multiple lineages.
Vertebrate Cdx genes encode homeodomain transcription factors related to caudal in Drosophila. The murine Cdx homologues Cdx1, Cdx2 and Cdx4 play important roles in anterior-posterior patterning of the embryonic axis and the intestine, as well as axial elongation. While our understanding of the ontogenic programs requiring Cdx function has advanced considerably, the molecular bases underlying these functions are less well understood. In this regard, Cdx1-Cdx2 conditional mutants exhibit abnormal somite formation, while loss of Cdx1-Cdx2 in the intestinal epithelium results in a shift in differentiation toward the Goblet cell lineage. The aim of the present study was to identify the Cdx-dependent mechanisms impacting on these events. Consistent with prior work implicating Notch signaling in these pathways, we found that expression of the Notch ligand Dll1 was reduced in Cdx mutants in both the intestinal epithelium and paraxial mesoderm. Cdx members occupied the Dll1 promoter both in vivo and in vitro, while genetic analysis indicated interaction between Cdx and Dll1 pathways in both somitogenesis and Goblet cell differentiation. These findings suggest that Cdx members operate upstream of Dll1 to convey different functions in two distinct lineages.
Department of Cellular and Molecular Medicine, University of Ottawa, 451 Smyth Road, Ottawa, Ontario, Canada.
Stephanie
S
Grainger
Jennifer
J
Lam
Joanne G A
JG
Savory
Alan J
AJ
Mears
Filippo M
FM
Rijli
David
D
Lohnes
D000818:Animals; D019521:Body Patterning / Q000235:genetics* / Q000502:physiology; D000071616:CDX2 Transcription Factor; D002135:Calcium-Binding Proteins; D002454:Cell Differentiation / Q000235:genetics*; D047369:Chromatin Immunoprecipitation; D024202:Electrophoretic Mobility Shift Assay; D020397:Goblet Cells / Q000166:cytology; D006652:Histological Techniques; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D017403:In Situ Hybridization; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism*; D007413:Intestinal Mucosa / Q000196:embryology*; D008648:Mesoderm / Q000196:embryology; D051379:Mice; D018345:Mice, Knockout; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology; D019170:Somites / Q000196:embryology* / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
D000071616:CDX2 Transcription Factor; D002135:Calcium-Binding Proteins; C491272:Cdx1 protein, mouse; C487514:Cdx2 protein, mouse; C512925:Dlk1 protein, mouse; D018398:Homeodomain Proteins; D036341:Intercellular Signaling Peptides and Proteins; D014157:Transcription Factors