scholarly journals Pectoral Fin Anomalies in tbx5a Knockdown Zebrafish Embryos Related to the Cascade Effect of N-Cadherin and Extracellular Matrix Formation

2019 ◽  
Vol 7 (3) ◽  
pp. 15 ◽  
Author(s):  
Jenn-Kan Lu ◽  
Tzu-Chun Tsai ◽  
Hsinyu Lee ◽  
Kai Hsia ◽  
Chih-Hsun Lin ◽  
...  

Functional knockdown of zebrafish tbx5a causes hypoplasia or aplasia of pectoral fins. This study aimed to assess developmental pectoral fin anomalies in tbx5a morpholino knockdown zebrafish embryos. The expression of cartilage-related genes in the tbx5a morphant was analyzed by DNA microarray, immunostaining, and thin-section histology to examine the detailed distribution of the extracellular matrix (ECM) during different pectoral fin developmental stages. Chondrogenic condensation (CC) in the tbx5a morpholino knockdown group was barely recognizable at 37 h postfertilization (hpf); the process from CC to endoskeleton formation was disrupted at 48 hpf, and the endoskeleton was only loosely formed at 72 hpf. Microarrays identified 18 downregulated genes in tbx5a-deficient embryos, including 2 fin morphogenesis-related (cx43, bbs7), 4 fin development-related (hoxc8a, hhip, axin1, msxb), and 12 cartilage development-related (mmp14a, sec23b, tfap2a, slc35b2, dlx5a, dlx1a, tfap2b, fmr1, runx3, cdh2, lect1, acvr2a, mmp14b) genes, at 24 and 30 hpf. The increase in apoptosis-related proteins (BAD and BCL2) in the tbx5a morphant influenced the cellular component of pectoral fins and resulted in chondrocyte reduction throughout the different CC phases. Furthermore, tbx5a knockdown interfered with ECM formation in pectoral fins, affecting glycosaminoglycans, fibronectin, hyaluronic acid (HA), and N-cadherin. Our results provide evidence that the pectoral fin phenotypic anomaly induced by tbx5a knockdown is related to disruption of the mesoderm and ECM, consequently interfering with mesoderm migration, CC, and subsequent endoskeleton formation.

Open Biology ◽  
2014 ◽  
Vol 4 (4) ◽  
pp. 140014 ◽  
Author(s):  
Aina Pi-Roig ◽  
Enrique Martin-Blanco ◽  
Carolina Minguillon

The transcription factor Tbx5 is expressed in the developing heart, eyes and anterior appendages. Mutations in human TBX5 cause Holt–Oram syndrome, a condition characterized by heart and upper limb malformations. Tbx5 -knockout mouse embryos have severely impaired forelimb and heart morphogenesis from the earliest stages of their development. However, zebrafish embryos with compromised tbx5 function show a complete absence of pectoral fins, while heart development is disturbed at significantly later developmental stages and eye development remains to be thoroughly analysed. We identified a novel tbx5 gene in zebrafish— tbx5b— that is co-expressed with its paralogue, tbx5a , in the developing eye and heart and hypothesized that functional redundancy could be occurring in these organs in embryos with impaired tbx5a function. We have now investigated the consequences of tbx5a and/or tbx5b downregulation in zebrafish to reveal that tbx5 genes have essential roles in the establishment of cardiac laterality, dorsoventral retina axis organization and pectoral fin development. Our data show that distinct relationships between tbx5 paralogues are required in a tissue-specific manner to ensure the proper morphogenesis of the three organs in which they are expressed. Furthermore, we uncover a novel role for tbx5 genes in the establishment of correct heart asymmetry in zebrafish embryos.


2015 ◽  
Vol 112 (52) ◽  
pp. 15940-15945 ◽  
Author(s):  
Tetsuya Nakamura ◽  
Jeff Klomp ◽  
Joyce Pieretti ◽  
Igor Schneider ◽  
Andrew R. Gehrke ◽  
...  

Extreme novelties in the shape and size of paired fins are exemplified by extinct and extant cartilaginous and bony fishes. Pectoral fins of skates and rays, such as the little skate (Batoid, Leucoraja erinacea), show a strikingly unique morphology where the pectoral fin extends anteriorly to ultimately fuse with the head. This results in a morphology that essentially surrounds the body and is associated with the evolution of novel swimming mechanisms in the group. In an approach that extends from RNA sequencing to in situ hybridization to functional assays, we show that anterior and posterior portions of the pectoral fin have different genetic underpinnings: canonical genes of appendage development control posterior fin development via an apical ectodermal ridge (AER), whereas an alternative Homeobox (Hox)–Fibroblast growth factor (Fgf)–Wingless type MMTV integration site family (Wnt) genetic module in the anterior region creates an AER-like structure that drives anterior fin expansion. Finally, we show that GLI family zinc finger 3 (Gli3), which is an anterior repressor of tetrapod digits, is expressed in the posterior half of the pectoral fin of skate, shark, and zebrafish but in the anterior side of the pelvic fin. Taken together, these data point to both highly derived and deeply ancestral patterns of gene expression in skate pectoral fins, shedding light on the molecular mechanisms behind the evolution of novel fin morphologies.


Development ◽  
1996 ◽  
Vol 123 (1) ◽  
pp. 255-262 ◽  
Author(s):  
F.J. van Eeden ◽  
M. Granato ◽  
U. Schach ◽  
M. Brand ◽  
M. Furutani-Seiki ◽  
...  

In the zebrafish, Danio rerio, a caudal and pectoral fin fold develop during embryogenesis. At larval stages the caudal fin fold is replaced by four different fins, the unpaired anal, dorsal and tail fins. In addition the paired pelvic fins are formed. We have identified a total of 118 mutations affecting larval fin formation. Mutations in 11 genes lead to abnormal morphology or degeneration of both caudal and pectoral fin folds. Most mutants survive to adulthood and form a surprisingly normal complement of adult fins. Mutations in nine genes result in an increased or reduced size of the pectoral fins. Interestingly, in mutants of one of these genes, dackel (dak), pectoral fin buds form initially, but later the fin epithelium fails to expand. Expression of sonic hedgehog mRNA in the posterior mesenchyme of the pectoral fin bud is initiated in dak embryos, but not maintained. Mutations in five other genes affect adult fin but not larval fin development. Two mutants, longfin (lof) and another longfin (alf) have generally longer fins. Stein und bein (sub) has reduced dorsal and pelvic fins, whereas finless (fls) and wanda (wan) mutants affect all adult fins. Finally, mutations in four genes causing defects in embryonic skin formation will be briefly reported.


eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Koh Onimaru ◽  
Shigehiro Kuraku ◽  
Wataru Takagi ◽  
Susumu Hyodo ◽  
James Sharpe ◽  
...  

The pectoral fins of ancestral fishes had multiple proximal elements connected to their pectoral girdles. During the fin-to-limb transition, anterior proximal elements were lost and only the most posterior one remained as the humerus. Thus, we hypothesised that an evolutionary alteration occurred in the anterior–posterior (AP) patterning system of limb buds. In this study, we examined the pectoral fin development of catshark (Scyliorhinus canicula) and revealed that the AP positional values in fin buds are shifted more posteriorly than mouse limb buds. Furthermore, examination of Gli3 function and regulation shows that catshark fins lack a specific AP patterning mechanism, which restricts its expression to an anterior domain in tetrapods. Finally, experimental perturbation of AP patterning in catshark fin buds results in an expansion of posterior values and loss of anterior skeletal elements. Together, these results suggest that a key genetic event of the fin-to-limb transformation was alteration of the AP patterning network.


Author(s):  
Ramón Lorenzo-Gómez ◽  
Rebeca Miranda-Castro ◽  
Noemí de-los-Santos-Álvarez ◽  
María Jesús Lobo-Castañón

Author(s):  
Ann-Kathrin Loerracher ◽  
Thomas Braunbeck

AbstractGiven the strong trend to implement zebrafish (Danio rerio) embryos as translational model not only in ecotoxicological, but also toxicological testing strategies, there is an increasing need for a better understanding of their capacity for xenobiotic biotransformation. With respect to the extrapolation of toxicological data from zebrafish embryos to other life stages or even other organisms, qualitative and quantitative differences in biotransformation pathways, above all in cytochrome P450-dependent (CYP) phase I biotransformation, may lead to over- or underestimation of the hazard and risk certain xenobiotic compounds may pose to later developmental stages or other species. This review provides a comprehensive state-of-the-art overview of the scientific knowledge on the development of the CYP1-4 families and corresponding phase I biotransformation and bioactivation capacities in zebrafish. A total of 68 publications dealing with spatiotemporal CYP mRNA expression patterns, activities towards mammalian CYP-probe substrates, bioactivation and detoxification activities, as well as metabolite profiling were analyzed and included in this review. The main results allow for the following conclusions: (1) Extensive work has been done to document mRNA expression of CYP isoforms from earliest embryonic stages of zebrafish, but juvenile and adult zebrafish have been largely neglected so far. (2) There is insufficient understanding of how sex- and developmental stage-related differences in expression levels of certain CYP isoforms may impact biotransformation and bioactivation capacities in the respective sexes and in different developmental stages of zebrafish. (3) Albeit qualitatively often identical, many studies revealed quantitative differences in metabolic activities of zebrafish embryos and later developmental stages. However, the actual relevance of age-related differences on the outcome of toxicological studies still needs to be clarified. (4) With respect to current remaining gaps, there is still an urgent need for further studies systematically assessing metabolic profiles and capacities of CYP isoforms in zebrafish. Given the increasing importance of Adverse Outcome Pathway (AOP) concepts, an improved understanding of CYP capacities appears essential for the interpretation and outcome of (eco)toxicological studies.


Author(s):  
Sanaz Bazaz Behbahani ◽  
Xiaobo Tan

In this paper, we propose a novel design for a pectoral fin joint of a robotic fish. This joint uses a flexible part to enable the rowing pectoral fin to feather passively and thus reduce the hydrodynamic drag in the recovery stroke. On the other hand, a mechanical stopper allows the fin to maintain its motion prescribed by the servomotor in the power stroke. The design results in net thrust even when the fin is actuated symmetrically for the power and recovery strokes. A dynamic model for this joint and for a pectoral fin-actuated robotic fish involving such joints is presented. The pectoral fin is modeled as a rigid plate connected to the servo arm through a pair of torsional spring and damper that describes the flexible joint. The hydrodynamic force on the fin is evaluated with blade element theory, where all three components of the force are considered due to the feathering degree of freedom of the fin. Experimental results on robotic fish prototype are provided to support the effectiveness of the design and the presented dynamic model. We utilize three different joints (with different sizes and different flexible materials), produced with a multi-material 3D printer, and measure the feathering angles of the joints and the forward swimming velocities of the robotic fish. Good match between the model predictions and experimental data is achieved, and the advantage of the proposed flexible joint over a rigid joint, where the power and recovery strokes have to be actuated at different speeds to produce thrust, is demonstrated.


Author(s):  
Blake V. DICKSON ◽  
Stephanie E. PIERCE

ABSTRACTThe fin-to-limb transition is heralded as one of the most important events in vertebrate evolution. Over the last few decades our understanding of how limbs evolved has significantly increased; but, hypotheses for why limbs evolved are still rather open. Fishes that engage their fins to ‘walk' along substrate may provide some perspective. The charismatic frogfishes are often considered to have the most limb-like fins, yet we still know little about their underlying structure. Here we reconstruct the pectoral fin musculoskeletal anatomy of the scarlet frogfish to identify adaptations that support fin-assisted walking behaviours. The data are compared to three additional anglerfish species: the oval batfish, which represents an independent acquisition of fin-assisted walking; and two pelagic deep-sea swimmers, the triplewart seadevil and ghostly seadevil. Our results clearly show broad musculoskeletal differences between the pectoral fins of swimming and walking anglerfish species. The frogfish and batfish have longer and more robust fins; larger, differentiated muscles; and better developed joints, including a reverse ball-and-socket glenoid joint and mobile ‘wrist'. Further, the frogfish and batfish show finer-scale musculoskeletal differences that align with their specific locomotor ecologies. Within, we discuss the functional significance of these anatomical features in relation to walking, the recurring evolution of similar adaptations in other substrate locomoting fishes, as well as the selective pressures that may underlie the evolution of limbs.


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