Hoxa-2 restricts the chondrogenic domain and inhibits bone formation during development of the branchial area

Development ◽  
1998 ◽  
Vol 125 (14) ◽  
pp. 2587-2597 ◽  
Author(s):  
B. Kanzler ◽  
S.J. Kuschert ◽  
Y.H. Liu ◽  
M. Mallo
Keyword(s):  
Bone Formation ◽  
Branchial Arch ◽  
Intramembranous Ossification ◽  
Expression Domain ◽  
Sox9 Expression ◽  
Molecular Analyses ◽  
Early Stages ◽  
Branchial Arches ◽  
Skeletal Formation ◽  
Dermal Bone

In Hoxa-2(−/−)embryos, the normal skeletal elements of the second branchial arch are replaced by a duplicated set of first arch elements. We show here that Hoxa-2 directs proper skeletal formation in the second arch by preventing chondrogenesis and intramembranous ossification. In normal embryos, Hoxa-2 is expressed throughout the second arch mesenchyme, but is excluded from the chondrogenic condensations. In the absence of Hoxa-2, chondrogenesis is activated ectopically within the rostral Hoxa-2 expression domain to form the mutant set of cartilages. In Hoxa-2(−/−)embryos the Sox9 expression domain is shifted into the normal Hoxa-2 domain. Misexpression of Sox9 in this area produces a phenotype resembling that of the Hoxa-2 mutants. These results indicate that Hoxa-2 acts at early stages of the chondrogenic pathway, upstream of Sox9 induction. We also show that Hoxa-2 inhibits dermal bone formation when misexpressed in its precursors. Furthermore, molecular analyses indicate that Cbfa1 is upregulated in the second branchial arches of Hoxa-2 mutant embryos suggesting that prevention of Cbfa1 induction might mediate Hoxa-2 inhibition of dermal bone formation during normal second arch development. The implications of these results on the patterning of the branchial area are discussed.

MyoD and Myf-5 define the specification of musculature of distinct embryonic origin

1998 ◽  
Vol 76 (6) ◽  
pp. 1079-1091 ◽  
Author(s):  
Boris Kablar ◽  
Atsushi Asakura ◽  
Kirsten Krastel ◽  
Chuyan Ying ◽  
Linda L May ◽  
...  
Keyword(s):  
Abdominal Wall ◽  
Expression Pattern ◽  
Branchial Arch ◽  
Precursor Cells ◽  
Mouse Development ◽  
Unique Role ◽  
Branchial Arches ◽  
Embryonic Origin ◽  
Body Wall Muscles ◽  
Myogenic Precursor

Mounting evidence supports the notion that Myf-5 and MyoD play unique roles in the development of epaxial (originating in the dorso-medial half of the somite, e.g. back muscles) and hypaxial (originating in the ventro-lateral half of the somite, e.g. limb and body wall muscles) musculature. To further understand how Myf-5 and MyoD genes co-operate during skeletal muscle specification, we examined and compared the expression pattern of MyoD-lacZ (258/-2.5lacZ and MD6.0-lacZ) transgenes in wild-type, Myf-5, and MyoD mutant embryos. We found that the delayed onset of muscle differentiation in the branchial arches, tongue, limbs, and diaphragm of MyoD-/- embryos was a consequence of a reduced ability of myogenic precursor cells to progress through their normal developmental program and not because of a defect in migration of muscle progenitor cells into these regions. We also found that myogenic precursor cells for back, intercostal, and abdominal wall musculature in Myf-5-/-embryos failed to undergo normal translocation or differentiation. By contrast, the myogenic precursors of intercostal and abdominal wall musculature in MyoD-/- embryos underwent normal translocation but failed to undergo timely differentiation. In conclusion, these observations strongly support the hypothesis that Myf-5 plays a unique role in the development of muscles arising after translocation of epithelial dermamyotome cells along the medial edge of the somite to the subjacent myotome (e.g., back or epaxial muscle) and that MyoD plays a unique role in the development of muscles arising from migratory precursor cells (e.g., limb and branchial arch muscles, tongue, and diaphragm). In addition, the expression pattern of MyoD-lacZ transgenes in the intercostal and abdominal wall muscles of Myf-5-/- and MyoD-/- embryos suggests that appropriate development of these muscles is dependent on both genes and, therefore, these muscles have a dual embryonic origin (epaxial and hypaxial).Key words: epaxial and hypaxial muscle, Myf-5, MyoD, mouse development, somite.

Jaw and branchial arch mutants in zebrafish I: branchial arches

Development ◽  
1996 ◽  
Vol 123 (1) ◽  
pp. 329-344 ◽  
Author(s):  
T.F. Schilling ◽  
T. Piotrowski ◽  
H. Grandel ◽  
M. Brand ◽  
C.P. Heisenberg ◽  
...  
Keyword(s):  
Neural Crest ◽  
Zebrafish Embryo ◽  
Neural Crest Cells ◽  
Branchial Arch ◽  
Pigment Cells ◽  
Pharyngeal Arches ◽  
Pectoral Fins ◽  
Branchial Arches ◽  
Group Members ◽  
The Brain

Jaws and branchial arches together are a basic, segmented feature of the vertebrate head. Seven arches develop in the zebrafish embryo (Danio rerio), derived largely from neural crest cells that form the cartilaginous skeleton. In this and the following paper we describe the phenotypes of 109 arch mutants, focusing here on three classes that affect the posterior pharyngeal arches, including the hyoid and five gill-bearing arches. In lockjaw, the hyoid arch is strongly reduced and subsets of branchial arches do not develop. Mutants of a large second class, designated the flathead group, lack several adjacent branchial arches and their associated cartilages. Five alleles at the flathead locus all lead to larvae that lack arches 4–6. Among 34 other flathead group members complementation tests are incomplete, but at least six unique phenotypes can be distinguished. These all delete continuous stretches of adjacent branchial arches and unpaired cartilages in the ventral midline. Many show cell death in the midbrain, from which some neural crest precursors of the arches originate. lockjaw and a few mutants in the flathead group, including pistachio, affect both jaw cartilage and pigmentation, reflecting essential functions of these genes in at least two neural crest lineages. Mutants of a third class, including boxer, dackel and pincher, affect pectoral fins and axonal trajectories in the brain, as well as the arches. Their skeletal phenotypes suggest that they disrupt cartilage morphogenesis in all arches. Our results suggest that there are sets of genes that: (1) specify neural crest cells in groups of adjacent head segments, and (2) function in common genetic pathways in a variety of tissues including the brain, pectoral fins and pigment cells as well as pharyngeal arches.

The branchial arches and HGF are growth-promoting and chemoattractant for cranial motor axons

Development ◽  
2000 ◽  
Vol 127 (8) ◽  
pp. 1751-1766 ◽  
Author(s):  
A. Caton ◽  
A. Hacker ◽  
A. Naeem ◽  
J. Livet ◽  
F. Maina ◽  
...  
Keyword(s):  
Growth Factor ◽  
Hepatocyte Growth Factor ◽  
Motor Neurons ◽  
Branchial Arch ◽  
Sensory Ganglia ◽  
Motor Axons ◽  
Collagen Gels ◽  
Branchial Arches ◽  
Growth Promoting ◽  
Hepatocyte Growth

During development, cranial motor neurons extend their axons along distinct pathways into the periphery. For example, branchiomotor axons extend dorsally to leave the hindbrain via large dorsal exit points. They then grow in association with sensory ganglia, to their targets, the muscles of the branchial arches. We have investigated the possibility that pathway tissues might secrete diffusible chemorepellents or chemoattractants that guide cranial motor axons, using co-cultures in collagen gels. We found that explants of dorsal neural tube or hindbrain roof plate chemorepelled cranial motor axons, while explants of cranial sensory ganglia were weakly chemoattractive. Explants of branchial arch mesenchyme were strongly growth-promoting and chemoattractive for cranial motor axons. Enhanced and oriented axon outgrowth was also elicited by beads loaded with Hepatocyte Growth Factor (HGF); antibodies to this protein largely blocked the outgrowth and orientation effects of the branchial arch on motor axons. HGF was expressed in the branchial arches, whilst Met, which encodes an HGF receptor, was expressed by subpopulations of cranial motor neurons. Mice with targetted disruptions of HGF or Met showed defects in the navigation of hypoglossal motor axons into the branchial region. Branchial arch tissue may thus act as a target-derived factor that guides motor axons during development. This influence is likely to be mediated partly by Hepatocyte Growth Factor, although a component of branchial arch-mediated growth promotion and chemoattraction was not blocked by anti-HGF antibodies.

Embryology of the head and neck

2013 ◽  
Author(s):  
Martin E. Atkinson
Keyword(s):  
Head And Neck ◽  
Neural Tube ◽  
Neck Region ◽  
Branchial Arch ◽  
Paraxial Mesoderm ◽  
Pharyngeal Arches ◽  
Branchial Arches ◽  
Aquatic Vertebrates ◽  
History Of ◽  
Further Development

Embryology and development have been covered after the main anatomical descriptions in the previous sections, but it is going to precede them in this section. The reason for this departure is that the embryonic development of the head and neck explains much of the mature anatomy which can seem illogical without its developmental history. The development of the head, face, and neck is an area of embryology where significant strides in our understanding have been made in the last few years. The development of the head is intimately related to the development of the brain outlined in Chapter 19 and its effects on shaping the head will be described in Chapters 32 and 33. The major thrust of this chapter is the description of the formation of structures called the pharyngeal (or branchial) arches and the fate of the tissues that contribute to them. All four embryonic germ layers contribute to the pharyngeal arches and their derivatives, hence to further development of the head and neck. Figure 21.1 is a cross section through the neck region of a 3-week old embryo after neurulation and folding described in Chapter 8. It shows the structures and tissues that contribute to the formation of the head and neck: • The neural tube situated posteriorly and the ectomesenchymal neural crest cells that arise as the tube closes; • The paraxial mesoderm anterolateral to the neural tube; • The endodermal foregut tube anteriorly; • The investing layer of ectoderm. The development of all these tissues is intimately interrelated. The pharyngeal arches are very ancient structures in the evolutionary history of vertebrates. The arches and their individual components have undergone many modifications during their long history. In ancestral aquatic vertebrates, as in modern fishes, water was drawn in through the mouth and expelled through a series of gill slits (or branchiae, hence the term ‘branchial arch’) in the sides of the pharynx. Oxygen was extracted as the water was passed over a gill apparatus supported by a branchial arch skeleton moved by branchial muscles controlled by branchial nerves. Although ventilation and respiration is now a function of the lungs in land vertebrates, the pharyngeal arches persist during vertebrate development.

scholarly journals Transcriptome profiling of the branchial arches reveals cell type composition and a conserved signature of neural crest cell invasion

2020 ◽  
Author(s):  
Jason A Morrison ◽  
Rebecca McLennan ◽  
Jessica M Teddy ◽  
Allison R Scott ◽  
Jennifer C Kasemeier-Kulesa ◽  
...  
Keyword(s):  
Neural Crest ◽  
Cell Invasion ◽  
Neural Crest Cell ◽  
Branchial Arch ◽  
Tissue Growth ◽  
Cell Populations ◽  
Label Free ◽  
Cell Type ◽  
Mesoderm Cell ◽  
Branchial Arches

ABSTRACTThe vertebrate branchial arches that give rise to structures of the head, neck, and heart form with very dynamic tissue growth and well-choreographed neural crest, ectoderm, and mesoderm cell dynamics. Although this morphogenesis has been studied by marker expression and fate-mapping, the mechanisms that control the collective migration and diversity of the neural crest and surrounding tissues remain unclear, in part due to the effects of averaging and need for cell isolation in conventional transcriptome analysis experiments of multiple cell populations. We used label free single cell RNA sequencing on 95,000 individual cells at 2 developmental stages encompassing formation of the first four chick branchial arches to measure the transcriptional states that define the cellular hierarchy and invasion signature of the migrating neural crest. The results confirmed basic features of cell type diversity and led to the discovery of many novel markers that discriminate between axial level and distal-to-proximal cell populations within the branchial arches and neural crest streams. We identified the transcriptional signature of the most invasive neural crest that is conserved within each branchial arch stream and elucidated a set of genes common to other cell invasion signatures in types in cancer, wound healing and development. These data robustly delineate molecularly distinct cell types within the branchial arches and identify important molecular transitions within the migrating neural crest during development.

scholarly journals Computed Tomography Findings of Complete Branchial Cleft Fistula

2020 ◽  
pp. 014556132095648
Author(s):  
Jackson King ◽  
Brian Mitchell
Keyword(s):  
Computed Tomography ◽  
Rare Variant ◽  
Branchial Arch ◽  
Neck Mass ◽  
Ct Imaging ◽  
Lateral Neck ◽  
Tonsillar Fossa ◽  
Branchial Arches ◽  
Branchial Cleft Anomalies ◽  
Branchial Cleft

Branchial cleft anomalies are embryonic remnants of the branchial arches and are described as the second most common congenital neck mass. Depending on their extent, these anomalies are classified as a cyst, sinus, or fistula with branchial cysts being the most common. Branchial cysts deriving from the second branchial arch are by far the most common, accounting for approximately 95% of all cases. Complete second branch arch fistulas with both an internal and external opening are a rare variant of this anomaly, and even less have been well-documented on computed tomography (CT) imaging in the literature. We present here a case of a 20-year-old female with CT findings consistent with a complete second branchial arch fistula extending from the tonsillar fossa to the external lateral neck.

Involvement of the sonic hedgehog, patched 1 and bmp2 genes in patterning of the zebrafish dermal fin rays

Development ◽  
1998 ◽  
Vol 125 (21) ◽  
pp. 4175-4184 ◽  
Author(s):  
L. Laforest ◽  
C.W. Brown ◽  
G. Poleo ◽  
J. Geraudie ◽  
M. Tada ◽  
...  
Keyword(s):  
Retinoic Acid ◽  
Sonic Hedgehog ◽  
Bone Matrix ◽  
Basal Layer ◽  
Pectoral Fin ◽  
Expression Domain ◽  
Fin Regeneration ◽  
Fin Rays ◽  
Dermal Bone ◽  
Fish Fins

The signaling molecule encoded by Sonic hedgehog (shh) participates in the patterning of several embryonic structures including limbs. During early fin development in zebrafish, a subset of cells in the posterior margin of pectoral fin buds express shh. We have shown that regulation of shh in pectoral fin buds is consistent with a role in mediating the activity of a structure analogous to the zone of polarizing activity (ZPA) (Akimenko and Ekker (1995) Dev. Biol. 170, 243–247). During growth of the bony rays of both paired and unpaired fins, and during fin regeneration, there does not seem to be a region equivalent to the ZPA and one would predict that shh would play a different role, if any, during these processes specific to fish fins. We have examined the expression of shh in the developing fins of 4-week old larvae and in regenerating fins of adults. A subset of cells in the basal layer of the epidermis in close proximity to the newly formed dermal bone structures of the fin rays, the lepidotrichia, express shh, and ptc1 which is thought to encode the receptor of the SHH signal. The expression domain of ptc1 is broader than that of shh and adjacent blastemal cells releasing the dermal bone matrix also express ptc1. Further observations indicate that the bmp2 gene, in addition to being expressed in the same cells of the basal layer of the epidermis as shh, is also expressed in a subset of the ptc1-expressing cells of the blastema. Amputations of caudal fins immediately after the first branching point of the lepidotrichia, and global administration of all-trans-retinoic acid, two procedures known to cause fusion of adjacent rays, result in a transient decrease in the expression of shh, ptc1 and bmp2. The effects of retinoic acid on shh expression occur within minutes after the onset of treatment suggesting direct regulation of shh by retinoic acid. These observations suggest a role for shh, ptc1 and bmp2 in patterning of the dermoskeleton of developing and regenerating teleost fins.

scholarly journals Histological Changes of the Mandibular Condyle in the Human Fetus at Early Stages of Gestation

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Wilfredo Molina
Keyword(s):  
Bone Formation ◽  
Human Fetus ◽  
Mandibular Condyle ◽  
Endochondral Bone Formation ◽  
Endochondral Bone ◽  
Histological Changes ◽  
Histological Sections ◽  
Early Stages ◽  
Mesenchymal Tissue ◽  
Periodic Reaction

Histochemical studies on the mandibular condyle of the human fetus at gestational ages 12, 14, and 16 weeks were performed. Methods. Histological sections were stained with Schiff’s periodic reaction for glicoproteins, hematoxiline eosine detects mesenchymal tissue and trichhromic stain for collagen. The ANOVA one-way test was used to evaluate the differences during stained zones in the three fetus groups. Results. The percentage of glycoproteins and mesenchymal tissue was denser at 12 weeks. This percentage decreases at 14 weeks and is less at 16 weeks. An increase in the amount of collagen in the studied weeks was observed. The percentages of glycoproteins, mesenchymal tissue, and collagen were significantly different; f = 4373, 9624.8, and 3674, P<0.0001 for the three studied groups. Conclusion. The endochondral bone formation of the mandibular condyle includes modifications of the quantities of glycoproteins, mesenchymal tissue, and collagen.

scholarly journals Muscular loading affects the 3D structure of both the mineralized rudiment and growth plate at early stages of bone formation

Bone ◽  
2021 ◽  
Vol 145 ◽  
pp. 115849
Author(s):  
Maria Pierantoni ◽  
Sophie Le Cann ◽  
Vivien Sotiriou ◽  
Saima Ahmed ◽  
Andrew J. Bodey ◽  
...  
Keyword(s):  
Bone Formation ◽  
Growth Plate ◽  
3D Structure ◽  
Early Stages

scholarly journals A distinct developmental programme for the cranial paraxial mesoderm in the chick embryo

Development ◽  
1998 ◽  
Vol 125 (17) ◽  
pp. 3461-3472 ◽  
Author(s):  
A. Hacker ◽  
S. Guthrie
Keyword(s):  
Neural Tube ◽  
Branchial Arch ◽  
Paraxial Mesoderm ◽  
Developmental Pathways ◽  
Myogenic Cells ◽  
Branchial Arches ◽  
Developmental Programme ◽  
Myogenic Markers ◽  
Somitic Mesoderm ◽  
Late Stages

Cells of the cranial paraxial mesoderm give rise to parts of the skull and muscles of the head. Some mesoderm cells migrate from locations close to the hindbrain into the branchial arches where they undergo muscle differentiation. We have characterised these migratory pathways in chick embryos either by DiI-labelling cells before migration or by grafting quail cranial paraxial mesoderm orthotopically. These experiments demonstrate that depending on their initial rostrocaudal position, cranial paraxial mesoderm cells migrate to fill the core of specific branchial arches. A survey of the expression of myogenic genes showed that the myogenic markers Myf5, MyoD and myogenin were expressed in branchial arch muscle, but at comparatively late stages compared with their expression in the somites. Pax3 was not expressed by myogenic cells that migrate into the branchial arches despite its expression in migrating precursors of limb muscles. In order to test whether segmental plate or somitic mesoderm has the ability to migrate in a cranial location, we grafted quail trunk mesoderm into the cranial paraxial mesoderm region. While segmental plate mesoderm cells did not migrate into the branchial arches, somitic cells were capable of migrating and were incorporated into the branchial arch muscle mass. Grafted somitic cells in the vicinity of the neural tube maintained expression of the somitic markers Pax3, MyoD and Pax1. By contrast, ectopic somitic cells located distal to the neural tube and in the branchial arches did not express Pax3. These data imply that signals in the vicinity of the hindbrain and branchial arches act on migrating myogenic cells to influence their gene expression and developmental pathways.

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