Nodal activity around Kupffer's vesicle depends on the T-box transcription factors Notail and Spadetail and on Notch signaling.
The node, or its zebrafish equivalent, Kupffers Vesicle (KV), is thought to generate laterality cues through cilia-dependent signaling. An interaction between Nodal ligands and Nodal antagonists around the node/KV is also required. Here we investigate whether loss of Brachyury/Notail or Tbx16/Spadetail disrupts the balance of Nodal ligands (Southpaw) and antagonists (Charon) around Kupffers Vesicle. Reduction of Spadetail or Notail disrupts expression of southpaw in the perinodal domains flanking Kupffers Vesicle. Similar to what was published for Notail, we find Spadetail is also required for expression of charon. We present evidence for the model that Notail has a direct role in regulating the charon promoter. In particular, a flanking genomic region with putative Notail binding sites can drive KV expression of a reporter in a Notail-dependent fashion. This region also contains motifs for CSL/RBP-J/Su(H). Consistent with this, we find charon expression is strongly Notch-dependent whereas perinodal southpaw expression is not.
Gourronc
Francoise
F
Department of Anatomy and Cell Biology, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242, USA.
Ahmad
Nadira
N
Nedza
Nicholas
N
Eggleston
Timothy
T
Rebagliati
Michael
M
D000818:Animals; D019521:Body Patterning; D029721:Drosophila Proteins / Q000502:physiology*; D004625:Embryo, Nonmammalian; D005326:Fetal Proteins / Q000502:physiology*; D055457:Nodal Protein; D051880:Receptors, Notch / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology*; D020825:T-Box Domain Proteins / Q000502:physiology*; D016212:Transforming Growth Factor beta / Q000502:physiology*; D015027:Zebrafish; D029961:Zebrafish Proteins / Q000502:physiology*; D000098908:Brachyury Protein
D029721:Drosophila Proteins; D005326:Fetal Proteins; D055457:Nodal Protein; D051880:Receptors, Notch; D020825:T-Box Domain Proteins; D016212:Transforming Growth Factor beta; D029961:Zebrafish Proteins; D000098908:Brachyury Protein; C497759:N protein, Drosophila; C112539:tbx16 protein, zebrafish