Loss of fish actinotrichia proteins and the fin-to-limb transition

  title={Loss of fish actinotrichia proteins and the fin-to-limb transition},
  author={Jing Zhang and Purva Wagh and D Guay and Luis S{\'a}nchez-Pulido and Bhaja K. Padhi and Vladimir Korzh and Miguel Andrade and M. A. Akimenko},
The early development of teleost paired fins is strikingly similar to that of tetrapod limb buds and is controlled by similar mechanisms. One early morphological divergence between pectoral fins and limbs is in the fate of the apical ectodermal ridge (AER), the distal epidermis that rims the bud. Whereas the AER of tetrapods regresses after specification of the skeletal progenitors, the AER of teleost fishes forms a fold that elongates. Formation of the fin fold is accompanied by the synthesis… 
A somitic contribution to the apical ectodermal ridge is essential for fin formation
It is demonstrated that apical-fold-inducing cells are progressively lost during gnathostome evolution; the absence of such cells within the tetrapod limb suggests that their loss may have been a necessary prelude to the attainment of limb-like structures in Devonian sarcopterygian fish.
Mechanism of pectoral fin outgrowth in zebrafish development
The results suggest that the timing of the A ER-AF transition mediates the differences between fins and limbs, and that the acquisition of a mechanism to maintain the AER was a crucial evolutionary step in the development of tetrapod limbs.
Fin-fold development in paddlefish and catshark and implications for the evolution of the autopod
Detailed aspects of paired fin development in the paddlefish Polyodon spathula and catshark Scyliorhinus canicula are characterized to explore aspects of this model in a broader phylogenetic context and suggest that limb-specific morphologies arose through evolutionary changes in the differentiation outcome of conserved early distal patterning compartments.
Structure and function of the median finfold in larval teleosts
An analytical model is proposed that predicts the extent of camber from the oblique arrangement of the actinotrichia and curvature of the body and experimental data confirm the predictions of the model.
HoxD expression in the fin-fold compartment of basal gnathostomes and implications for paired appendage evolution
The results demonstrate a collinear pattern of nesting in early fin buds that includes HoxD14, a gene previously thought to be isolated from global Hox regulation, and fuel new hypotheses about the evolution of cluster regulation and the potential downstream differentiation outcomes of distinct Hox D-regulated compartments.
Differential actinodin1 regulation in embryonic development and adult fin regeneration in Danio rerio
C cis-acting regulatory elements that are required for tissue-specific expression as well as full recapitulation of actinodin1 expression during adulthood are identified and provided with useful molecular tools for the enhancement of transgene expression in adulthood.


An analysis of in vivo cell migration during teleost fin morphogenesis.
The migration of the mesenchymal cells between 135 and 220 h of development is investigated using Nomarski interference contrast microscopy and time-lapse video recording, which revealed that, generally, aligned processes were in close association with the surface of the actinotrichial fibrils and not the spaces between them.
Comparative Fine Structure of the Actinotrichia (Elastoidin) in Developing Teleost and Dipnoi Fish Fins
So far, on the basis of morphology and fine structure, actinotrichia are considered to be homologues of ceratotichia found in Chondrichthyes, where elastoidin has been biochemically and biophysically analyzed.
Initiation of the actinotrichial development in the early fin bud of the fish, Salmo
Ultrastructural analysis of initial development of actinotrichia, the skeleton anlage of the pelvic fin buds, was performed on the rainbow trout and morphological data suggest that the epidermal pseudoapical cap probably initiates the development ofActinotRichia.
Early pectoral fin development and morphogenesis of the apical ectodermal ridge in the killifish, Aphyosemion scheeli
  • A. Wood
  • Biology
    The Anatomical record
  • 1982
It has been found that in the killifish the distal epithelium of the pectoral fin bud forms a morphologically distinct apical ectodermal ridge along its entire distal margin that is a relatively more prominent feature than its counterpart in various tetrapod systems.
Hox gene expression in teleost fins and the origin of vertebrate digits
A scheme for the fin–limb transition in which the distal autopods (digits) are neomorphic structures produced by unequal proliferation of the posterior part of an ancestral appendix is suggested.
Modulation of epidermal cell shaping and extracellular matrix during caudal fin morphogenesis in the zebra fish Brachydanio rerio.
During early stages of fold production a temporary set of previously unreported extracellular cross fibres spans the subepidermal space at right angles to actinotrichia, which could be advantageous for maintaining the structural integrity of the early fin fold.
BMPs negatively regulate structure and function of the limb apical ectodermal ridge.
It is found that BMPs limit limb outgrowth by promoting AER regression, as BMP inhibition results in persistence of the AER, prolonged Fgf expression and excess soft-tissue growth.