XB-ART-36267Dev Dyn 2007 Sep 01;2369:2713-20. doi: 10.1002/dvdy.21280.
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Integrin alpha5 is required for somite rotation and boundary formation in Xenopus.
The morphogenesis of somites in Xenopus laevis is characterized by a complex process of cell turning that requires coordinated regulation of cell shape, adhesion, and motility. The integrin alpha5 subunit has been implicated in the formation of somite boundaries in organisms utilizing epithelialization to create morphologically distinct somites, but its function has not been examined in Xenopus. We used a splice-blocking morpholino to knock down expression of integrin alpha5 during somite formation. Loss of integrin alpha5 delayed somite turning and accumulation of integrin beta1 at somite boundaries, and disrupted the fibronectin matrix surrounding developing somites. Irregular somite boundaries with a sparse and discontinuous fibronectin matrix formed upon eventual completion of somite turning. Recovery of somite morphology was improved, but still incomplete in far posterior somites. These data demonstrate that the role of integrin alpha5 in somite boundary formation is conserved in a species using a unique mechanism of somitogenesis.
PubMed ID: 17685483
Article link: Dev Dyn
Species referenced: Xenopus laevis
Genes referenced: ctnnb1 fn1 itga5 itgb1 myod1
Antibodies: Itgb1 Ab1
Morpholinos: itga5 MO1
Article Images: [+] show captions
|Figure 3. Patterning and morphology of the presomitic mesoderm in embryos injected with the intg alpha 5 MO. A-D: In situ hybridization with a probe for MyoD in a stage-19 (A,B) and a stage-25 (C,D) embryo, showing uninjected (A) and intg alpha 5 MO-injected (B) sides of an embryo, and control MO injected (C) and intg alpha 5 MO-injected embryos (D) Arrows in D indicate individual somites. E,F: Immunofluorescence staining for beta -catenin (E, red in F) and GFP (green in F) showing normal morphology of the presomitic mesoderm in cells exposed to the intg alpha 5 MO (GFP positive cells, bottom). E: Inverse image is shown to highlight cell borders. Asterisks in E mark somites in the process of turning. Anterior is on the left in all images. Scale bar = 100 mu m.|