<i>Bapx1</i> is required for jaw joint development in amphibians

Lukas, Paul; Olsson, Lennart

doi:10.1111/ede.12267

Cited by 18 publications

(23 citation statements)

References 45 publications

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“…NK3 homeobox 2 (nkx3.2) was rst identi ed in the drosophila model and is part of the NK family of homeobox genes (16). Homologues of the gene have been found in vertebrates (including zebra sh and humans) and are dorsally expressed predominately in the rst pharyngeal arch where the gene is essential for proper joint formation (16). Knockdown of nkx3.2 causes mandibular jaw joint fusion in amphibians (16).…”

Section: Nkx32 Expression Decreased In Hspg2 Morphantsmentioning

confidence: 99%

Knockdown of hspg2 is associated with mandibular jaw joint fusion and neural crest cell dysfunction in zebrafish

Castellanos¹,

Reyes-Nava²,

Quintana³

2020

Preprint

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Background: Heparan sulfate proteoglycan 2 (HSPG2) encodes for perlecan, a large proteoglycan that plays an important role in cartilage formation, cell adhesion, and basement membrane stability. Mutations in HSPG2 have been associated with Schwartz-Jampel syndrome and Dyssegmental Dysplasia Silverman-Handmaker Type, two disorders characterized by skeletal abnormalities. These data indicate a function for HSPG2 in cartilage development/maintenance. However, the mechanisms in which HSPG2 regulates cartilage development are not completely understood. Here, we explored the relationship between this gene and craniofacial development through morpholino-mediated knockdown of hspg2 in zebrafish. Results: Knockdown of hspg2 resulted in a fusion of the mandibular jaw joint at 5 days post fertilization (dpf). We surmised that defects in mandible development were a consequence of neural crest cell (NCC) dysfunction, as these multipotent progenitors produce the cartilage of the head. Early NCC development was normal in morphant animals as measured by distal-less homeobox 2a (dlx2a) and SRY-box transcription factor 10 (sox10) expression at 1 dpf. However, subsequent analysis at later stages of development (4 dpf) revealed a decrease in the number of Sox10 + and Collagen, type II, alpha 1a (Col2a1a)+ cells within the mandibular jaw joint region of morphants relative to random control injected embryos. Concurrently, morphants showed a decreased expression of NK3 homeobox 2 (nkx3.2), a jaw joint molecular marker at 4 dpf. Conclusions: Collectively, these data suggest a complex role for hspg2 in jaw joint formation and late stage NCC differentiation.

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Section: Nkx32 Expression Decreased In Hspg2 Morphantsmentioning

confidence: 99%

Knockdown of hspg2 is associated with mandibular jaw joint fusion and neural crest cell dysfunction in zebrafish

Castellanos¹,

Reyes-Nava²,

Quintana³

2020

Preprint

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“…Tadpoles of the anuran Bombina orientalis (Boulenger, 1890) display a generalized morphology close to the basal state in anurans (Cannatella & De Sá, 1993; McDiarmid & Altig, 1999) and are well suited for studies of the sequence of skeletal development. B. orientalis has been used for different types of investigations, such as, for example, chimeric experiments (Wagner, 1949, 1959), descriptions of different morphological aspects (Haas, 1997; Ridewood, 1897; Sokol, 1975; Wassersug & Hoff, 1982), embryonic staging (Prema, 1981; Sussman & Betz, 1978), ossification sequences (Hanken & Hall, 1984; Maglia & Púgener, 1998), neural crest extirpations (Olsson, Falck, Lopez, Cobb, & Hanken, 2001; Olsson & Hanken, 1996), knockdown experiments (Lukas & Olsson, 2018b), toxicological surveys (Park, Song, Kim, & Gye, 2017), and peptide research (Xiang et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

Sequence of chondrocranial development in the oriental fire bellied toad Bombina orientalis

Lukas

Olsson

2020

Journal of Morphology

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The vertebrate head as a major novelty is directly linked to the evolutionary success of the vertebrates. Sequential information on the embryonic pattern of cartilaginous head development are scarce, but important for the understanding of its evolution. In this study, we use the oriental fire bellied toad, Bombina orientalis, a basal anuran to investigate the sequence and timing of larval cartilaginous development of the head skeleton from the appearance of mesenchymal Anlagen in post-neurulation stages until the premetamorphic larvae. We use different methodological approaches like classic histology, clearing and staining, and antibody staining to examine the larval skeletal morphology. Our results show that in contrast to other vertebrates, the ceratohyals are the first centers of chondrification. They are followed by the palatoquadrate and the basihyal. The latter later fuses to the ceratohyal and the branchial basket. Anterior elements like Meckel's cartilage and the rostralia are delayed in development and alter the ancestral anterior posterior pattern observed in other vertebrates. The ceratobranchials I-IV, components of the branchial basket, follow this strict anterior-posterior pattern of chondrification as reported in other amphibians.Chondrification of different skeletal elements follows a distinct pattern and the larval skeleton is nearly fully developed at Gosner Stage 28. We provide baseline data on the pattern and timing of early cartilage development in a basal anuran species, which may serve as guidance for further experimental studies in this species as well as an important basis for the understanding of the evolutionary changes in head development among amphibians and vertebrates.

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“…This is likely the 396 widespread condition among jawed vertebrates. Nkx3.2 knockdown also results in fusion between the 397 palatoquadrate and Meckel's cartilage in amphibians (Lukas and Olsson, 2018a), and a similar 398 phenotype is observed in chicks with ectopic expression of BMP4 and FGF8 that repressed The late onset and topology of skull/jaw remodeling suggests that nkx3.2 -/zebrafish accommodate the 424 loss of the jaw joint via a plastic response. Other than the absence of jaw joint, nkx3.2 -/zebrafish 425 appear normal until metamorphosis (14-21 dpf) ( Fig.…”

Section: The Adult Nkx32 -/Phenotype Accommodates Functional Jaw Losmentioning

confidence: 87%

nkx3.2mutant zebrafish accommodate jaw joint loss through a phenocopy of the head shapes of Paleozoic jawless fish

Miyashita

Baddam

Smeeton

et al. 2019

Preprint

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The vertebrate jaw is a versatile feeding apparatus that facilitated explosive diversification. To function, it requires a joint between the upper and lower jaws, so jaw joint defects - such as osteoarthritis or even ankylosis - are often highly disruptive and difficult to study. To describe consequences of jaw-joint dysfunction, we engineered two independent null alleles of a single jaw-joint marker gene, nkx3.2, in zebrafish. These mutations caused zebrafish to become functionally jawless via fusion of the upper and lower jaw cartilages (ankylosis). Despite lacking jaw joints, nkx3.2 mutants survive to adulthood and accommodate this defect by: a) remodeling their skulls; and b) altering their behavior from suction feeding to ram feeding. As a result of remodeling, nkx3.2 mutants developed superficial similarities to the skull shapes observed in two lineages of ancient jawless vertebrates (anaspids and furcacaudiid thelodonts), including: a fixed open gape, reduced snout, and enlarged branchial region. However, no homology exists in individual skull elements between these taxa, and most of the modified elements in the mutant zebrafish occur outside known expression domains of nkx3.2. Therefore, we interpret the adult nkx3.2 phenotype not as a reversal to an ancestral state, but as convergence due to similar functional requirement of feeding without moveable jaws. This remarkable convergence strongly suggests that jaw movements themselves dramatically influence the development of jawed vertebrate skulls, which implies that functionally viable skull morphologies are finite, with or without functional jaws. Because nkx3.2 null zebrafish display prominent joint ankylosis, drastically modified skull shape, and altered feeding behaviors, these mutants provide a unique model with which to investigate mechanisms of skeletal remodeling and joint diseases.

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Bapx1 is required for jaw joint development in amphibians

Cited by 18 publications

References 45 publications

Knockdown of hspg2 is associated with mandibular jaw joint fusion and neural crest cell dysfunction in zebrafish

Knockdown of hspg2 is associated with mandibular jaw joint fusion and neural crest cell dysfunction in zebrafish

Sequence of chondrocranial development in the oriental fire bellied toad Bombina orientalis

nkx3.2mutant zebrafish accommodate jaw joint loss through a phenocopy of the head shapes of Paleozoic jawless fish

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