... of jaw evolution by transformation of a gill arch have been challenged, and the pseudobranch has alternatively been considered a specialised derivative of the second (hyoid) pharyngeal arch. Here, we demonstrate in the skate ( Leucoraja erinacea ) that the pseudobranch does, in fact, derive from...

...Kazunori Okada; Shinji Takada ABSTRACT Pharyngeal arches (PAs) are segmented by endodermal outpocketings called pharyngeal pouches (PPs). Anterior and posterior PAs appear to be generated by different mechanisms, but it is unclear how the anterior and posterior PAs combine. Here, we addressed...

... of heart and head muscles, unexpectedly gives rise to a broad range of pharyngeal structures implicated in muscle patterning, pharyngeal pathology and evolution. CPM Neural crest cells Pharyngeal arch Pharynx Tbx1 22q11.2 deletion syndrome Mouse Bourses du Gouvernement Français...

.... Genet.   21 , 70 - 71 . 10.1038/5007 Sperber , S. M. and Dawid , I. B. ( 2008 ). barx1 is necessary for ectomesenchyme proliferation and osteochondroprogenitor condensation in the zebrafish pharyngeal arches . Dev. Biol.   321 , 101 - 110 . 10.1016/j.ydbio.2008.06.004...

...Kazunori Okada; Keiji Inohaya; Takeshi Mise; Akira Kudo; Shinji Takada; Hiroshi Wada ABSTRACT A striking characteristic of vertebrate development is the pharyngeal arches, which are a series of bulges on the lateral surface of the head of vertebrate embryos. Although each pharyngeal arch...

..., whereas its late inactivation results in a hypomorphic auricle, mimicking the human HOXA2 mutant condition. By genetic fate mapping we found that the mouse auricle (or pinna) derives from the Hoxa2 -expressing neural crest-derived mesenchyme of the second pharyngeal arch, and not from a composite of first...

... signals, such as Endothelin 1 (Edn1) and Jagged/Notch, which pattern the dorsal-ventral (DV) axis of the pharyngeal arches. Here, we use transgenic zebrafish to monitor and perturb BMP signaling during arch formation. With a BMP-responsive transgene, Tg(Bre:GFP), we show active BMP signaling in neural...

...-ku, Saitama 338-8570, Japan Competing interests statement 1 11 2010 © 2011. Ripply3 Tbx1 Cardiovascular Endoderm Pharyngeal arch Thymus Mouse The pharyngeal apparatus is a transient structure that is formed ventrolateral to the hindbrain...

... tract septation and thymic and dorsal root ganglia development. Dicer mutant embryos had reduced expression of Dlx2 , a transcriptional regulator of pharyngeal arch development, in the first pharyngeal arch (PA1). miR-452 was enriched in NCCs, was sufficient to rescue Dlx2 expression in Dicer mutant...

...-like phenotypes. Additionally, reducing the gene dosage of Fgf8 rescued pharyngeal arch artery defects caused by loss of Ctnnb1 . These findings identify Wnt—β-catenin signaling as a crucial upstream regulator of a Tbx1—Fgf8 signaling pathway and suggest that factors that affect Wnt—β-catenin signaling...

... mutants display anterior transformations of pharyngeal arches due to progressive loss of anterior Hox gene expression. Brpf1 functions in association with the histone acetyltransferase Moz (Myst3), an interaction mediated by the N-terminal domain of Brpf1, and promotes histone acetylation in vivo. Brpf1...

...) receptors. During embryogenesis, the Edn1/Ednra signaling is thought to regulate the dorsoventral axis patterning of pharyngeal arches via Dlx5/Dlx6 upregulation. To further clarify the underlying mechanism, we have established mice in which gene cassettes can be efficiently knocked-in into the Ednra locus...

.... Knockdown of Ednra1 leads to fusions between upper- and lower-jaw cartilages, whereas the combined loss of Ednra1 and Ednra2 eliminates the lower jaw, similar to edn1 -/- mutants. edn1 is expressed in pharyngeal arch ectoderm, mesoderm and endoderm. Tissue-mosaic studies indicate that, among these tissues...

... of post-migratory neural crest cells, that gives rise to the cartilages of the anterior neurocranium and the pterygoid process of the palatoquadrate in the upper jaw, condenses upon the upper or roof layer of the stomodeal ectoderm in the first pharyngeal arch. We observe that in mutants for the Hh co...

... with a constellation of heart, outflow tract, great vessel and pharyngeal gland defects that phenocopies human deletion 22q11 syndromes, such as DiGeorge. We postulate that these Fgf8 hypomorphic phenotypes result from disruption of local FGF8 signaling from pharyngeal arch epithelia to mesenchymal cells populating...

... development Patterning Fgf Shh Neuroectoderm Facial ectoderm Neural crest Frontonasal process FNP Branchial arch Pharyngeal arch Quail Chick Almost 100 years of exploration into the mechanisms underlying morphogenesis has revealed that pattern formation is a remarkably conserved...

... and joints in the anterior pharyngeal arches of young larvae. Here we present genetic analyses in the zebrafish of two edn1 downstream targets, the bHLH transcription factor Hand2 and the homeobox transcription factor Bapx1, that mediate dorsoventral (DV) patterning in the anterior pharyngeal arches. First...

...Charles B. Kimmel; Bonnie Ullmann; Macie Walker; Craig T. Miller; Justin G. Crump Endothelin 1 (Edn1), a secreted peptide expressed ventrally in the primordia of the zebrafish pharyngeal arches, is required for correct patterning of pharyngeal cartilage development. We have studied mutants...

...Radwan Abu-Issa; Graham Smyth; Ida Smoak; Ken-ichi Yamamura; Erik N. Meyers We present here an analysis of cardiovascular and pharyngeal arch development in mouse embryos hypomorphic for Fgf8 . Previously, we have described the generation of Fgf8 compound heterozygous ( Fgf8 neo/– ) embryos...

... in the environment of postmigratory neural crest cells to specify ventral arch fates. Our mosaic analyses further show that suc/et-1 nonautonomously functions in mesendoderm for ventral arch muscle formation. Collectively our results support a model for dorsoventral patterning of the gnathostome pharyngeal arches...