... compare TM formation along the anterior-posterior axis in these animals using Hoxa2 expression as a marker of the second pharyngeal arch (PA2). In chick, the EAM begins to invaginate at the surface ectoderm of PA2, not at the first pharyngeal cleft, and the entire TM forms in PA2. Chick-quail chimera...

... the positional information encoded by Hox genes is translated into morphogenetic changes. Here, we conclusively demonstrate that Six2 is a direct downstream target of Hoxa2 in vivo and show that the ectopic expression of Six2 , observed in the absence of Hoxa2, contributes to the Hoxa2 mouse mutant phenotype. We...

...Eva Kutejova; Bettina Engist; Moisés Mallo; Benoît Kanzler; Nicoletta Bobola The Hoxa2 transcription factor acts during development of the second branchial arch. As for most of the developmental processes controlled by Hox proteins, the mechanism by which Hoxa2 regulates the morphology of second...

... University School of Medicine, Stanford, CA 94305, USA 17 2 2004 © 2004. 2004 moz Hox hoxa2 Zebrafish Cranial neural crest Bapx1 Goosecoid Homeosis Pharynx The jaw forms embryonically as hinged dorsal and ventral cartilages in the first (mandibular) pharyngeal arch...

... analyzed how Hoxa2 specifies segmental identity in the second branchial arch. Using a subtraction approach, we found that Ptx1 was upregulated in the second arch mesenchyme of Hoxa2 mutants. This upregulation has functional significance because, in Hoxa2 -/- ; Ptx1 -/- embryos, the Hoxa2 -/- phenotype...

...George A. Grammatopoulos; Esther Bell; Leah Toole; Andrew Lumsden; Abigail S. Tucker ABSTRACT Overexpression of Hoxa2 in the chick first branchial arch leads to a transformation of first arch cartilages, such as Meckel’s and the quadrate, into second arch elements, such as the tongue skeleton...

... of these genes, Hoxa1 and Hoxa2 , have been shown to be required for proper patterning of the early mouse hindbrain and the associated neural crest. To determine the extent to which these two genes function together to pattern the hindbrain, we generated mice simultaneously mutant at both loci. The hindbrain...

...Richard J. T. Wingate; Mary E. Hatten SUMMARY We have used a combination of quail-chick fate-mapping techniques and dye labelling to investigate the development of the avian cerebellum. Using Hoxa2 as a guide for the microsurgical construction of quail-chick chimaeras, we show that the caudal...

...Mark Maconochie; Ramachandran Krishnamurthy; Stefan Nonchev; Pascal Meier; Miguel Manzanares; Pamela J. Mitchell; Robb Krumlauf Hoxa2 is expressed in cranial neural crest cells that migrate into the second branchial arch and is essential for proper patterning of neural-crest-derived structures...