Thylacine 1 is expressed segmentally within the paraxial mesoderm of the Xenopus embryo and interacts with the Notch pathway.
The presomitic mesoderm of vertebrates undergoes a process of segmentation in which cell-cell interactions mediated by the Notch family of receptors and their associated ligands are involved. The vertebrate homologues of Drosophila &Dgr ; are expressed in a dynamic, segmental pattern within the presomitic mesoderm, and alterations in the function of these genes leads to a perturbed pattern of somite segmentation. In this study we have characterised Thylacine 1 which encodes a basic helix-loop-helix class transcription activator. Expression of Thylacine is restricted to the presomitic mesoderm, localising to the anterior half of several somitomeres in register with domains of X-Delta-2 expression. Ectopic expression of Thylacine in embryos causes segmentation defects similar to those seen in embryos in which Notch signalling is altered, and these embryos also show severe disruption in the expression patterns of the marker genes X-Delta-2 and X-ESR5 within the presomitic mesoderm. Finally, the expression of Thylacine is altered in embryos when Notch signalling is perturbed. These observations suggest strongly that Thylacine 1 has a role in the segmentation pathway of the Xenopus embryo, by interacting with the Notch signalling pathway.
Sparrow
D B
DB
Division of Developmental Biology, National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK.
Jen
W C
WC
Kotecha
S
S
Towers
N
N
Kintner
C
C
Mohun
T J
TJ
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D019521:Body Patterning / Q000235:genetics*; D002450:Cell Communication / Q000235:genetics*; D015870:Gene Expression; D018257:Helix-Loop-Helix Motifs; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins / Q000096:biosynthesis / Q000378:metabolism*; D008648:Mesoderm; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000302:isolation & purification; D051880:Receptors, Notch; D017386:Sequence Homology, Amino Acid; D019170:Somites; D014018:Tissue Distribution; D015534:Trans-Activators / Q000096:biosynthesis / Q000235:genetics*; D014157:Transcription Factors; D014158:Transcription, Genetic; D014981:Xenopus / Q000196:embryology*; D029867:Xenopus Proteins
D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D012333:RNA, Messenger; D051880:Receptors, Notch; D015534:Trans-Activators; D014157:Transcription Factors; D029867:Xenopus Proteins; C064045:delta protein; C112957:thylacine 1 protein, Xenopus; C112958:thylacine 2 protein, Xenopus