scholarly journals Transcriptional components of anteroposterior positional information during zebrafish fin regeneration

Development ◽  
2013 ◽  
Vol 140 (18) ◽  
pp. 3754-3764 ◽  
Author(s):  
G. Nachtrab ◽  
K. Kikuchi ◽  
V. A. Tornini ◽  
K. D. Poss

2019 ◽  
Author(s):  
Scott Stewart ◽  
Gabriel A. Yette ◽  
Heather K. Le Bleu ◽  
Astra L. Henner ◽  
Joshua A. Braunstein ◽  
...  

ABSTRACTRegenerating fish fins return to their original size and shape regardless of the nature or extent of injury. Prevailing models for this longstanding mystery of appendage regeneration speculate fin cells maintain uncharacterized positional identities that instruct outgrowth after injury. Using zebrafish, we find differential Wnt production correlates with the extent of regeneration across the caudal fin. We identify Dachshund transcription factors as markers of distal blastema cells that produce Wnt and thereby promote a pro-progenitor and -proliferation environment. We show these Dach-expressing “niche cells” derive from mesenchyme populating cylindrical and progressively tapered fin rays. The niche pool, and consequently Wnt, steadily dissipates as regeneration proceeds; once exhausted, ray and fin growth stops. Supported by mathematical modeling, we show longfint2 zebrafish regenerate exceptionally long fins due to a perdurant niche, representing a “broken countdown timer”. We propose regenerated fin size is dictated by the amount of niche formed upon damage, which simply depends on the availability of intra-ray mesenchyme defined by skeletal girth at the injury site. Likewise, the fin reestablishes a tapered ray skeleton because progenitor osteoblast output reflects diminishing niche size. This “transpositional scaling” model contends mesenchyme-niche state transitions and positional information provided by self-restoring skeletal geometry rather than cell memories determine a regenerated fin’s size and shape.



2019 ◽  
Author(s):  
Scott Stewart ◽  
Heather K. Le Bleu ◽  
Gabriel A. Yette ◽  
Astra L. Henner ◽  
Amy E. Robbins ◽  
...  

ABSTRACTOrgans stop growing to achieve the size and shape characteristic of the species and in scale with the animal’s body. Likewise, regenerating organs sense injury extents to instruct appropriate replacement growth. Fish fins exemplify both phenomena through their tremendous diversity of form and remarkably robust regeneration. The classic zebrafish mutant longfin develops and regenerates dramatically elongated fins and underlying bony ray skeleton. Here, we show longfin mutant chromosome 2 overexpresses kcnh2a, a voltage-gated potassium channel related to human ether-a-go-go. Genetic disruption of kcnh2a in cis rescues the dominant longfin eponymous phenotype, indicating longfin is a regulatory allele of kcnh2a. We find regenerative fin overgrowth in longfin is characterized by a prolonged outgrowth period rather than increased maximal growth rate. Accordingly, small molecule inhibition of Kcnh2a during late but not early stages of fin regeneration fully suppresses longfin fin overgrowth. Blastula stage transplantations show longfin-expressed kcnh2a acts tissue autonomously in the fin intra-ray mesenchymal lineage, where it is concordantly ectopically expressed. We use temporal delivery of FK506 to show the Ca2+-dependent phosphatase calcineurin likewise entirely acts late in regeneration to attenuate the fin outgrowth period. Epistasis experiments suggest longfin-expressed Kcnh2a inhibits calcineurin signaling to supersede endogenous growth cessation signals. Our results indicate how ion signaling within a growth-determining mesenchyme-lineage controls fin size and morphological variation by tuning outgrowth periods rather than altering positional information.



Impact ◽  
2019 ◽  
Vol 2019 (10) ◽  
pp. 12-14
Author(s):  
Akira Kawai ◽  
Masahiro Kenmotsu

Traffic congestion in parking lots is a common phenomenon across the world and larger commercial facilities with multiple parking areas may be particularly affected as many users struggle to gain access to sought-after parking spots close to their destinations. These popular zones often see traffic jams forming as many vehicles arrive within these regions, while less popular areas may remain free from congestion. This creates a very uneven distribution of traffic, with motorists in popular areas becoming trapped and unable to leave bottleneck regions. As a result, the car park management industry has taken an interest in research into parking guidance. Parking guidance has been developed to help improve efficiencies in car parks, guiding drivers to specific spaces using GPS technology to highlight free spaces near their location detailing the most efficient way to get to that spot. Associate Professor Akira Kawai, who is based at Shiga University in Japan, has been working on a KAKEN project that seeks to leverage real-time positional information to help guide drivers to free spaces within parking lots.







Author(s):  
Adrian J Barake ◽  
Heather Mitchell ◽  
Constantino Stavros ◽  
Mark F Stewart ◽  
Preety Srivastava

Efficient recruitment to Australia’s most popular professional sporting competition, the Australian Football League (AFL), requires evaluators to assess athlete performances in many lower tier leagues that serve as pathways. These competitions and their games are frequent, widespread, and challenging to track. Therefore, independent, and reliable player performance statistics from these leagues are paramount. This data, however, is only meaningful to recruiters from AFL teams if accurate player positions are known, which was not the case for the competitions from which most players were recruited. This paper explains how this problem was recently solved, demonstrating a process of knowledge translation from academia to industry, that bridged an important gap between sports science, coaching and recruiting. Positional information which is only available from the AFL competition was used to benchmark and develop scientific classification methods using only predictor variables that are also measured in lower tier competitions. Specifically, a Multinomial Logistic model was constructed to allocate players into four primary positions, followed by a Binary Logit model for further refinement. This novel technique of using more complete data from top tier competitions to help fill informational deficiencies in lower leagues could be extended to other sports that face similar issues.



Genetics ◽  
1998 ◽  
Vol 149 (1) ◽  
pp. 257-275 ◽  
Author(s):  
Sophie Netter ◽  
Marie-Odile Fauvarque ◽  
Ruth Diez del Corral ◽  
Jean-Maurice Dura ◽  
Dario Coen

AbstractWe used the white gene as an enhancer trap and reporter of chromatin structure. We collected white+ transgene insertions presenting a peculiar pigmentation pattern in the eye: white expression is restricted to the dorsal half of the eye, with a clear-cut dorsal/ventral (D/V) border. This D/V pattern is stable and heritable, indicating that phenotypic expression of the white reporter reflects positional information in the developing eye. Localization of these transgenes led us to identify a unique genomic region encompassing 140 kb in 69D1–3 subject to this D/V effect. This region contains at least three closely related homeobox-containing genes that are constituents of the iroquois complex (IRO-C). IRO-C genes are coordinately regulated and implicated in similar developmental processes. Expression of these genes in the eye is regulated by the products of the Polycomb -group (Pc-G) and trithorax-group (trx-G) genes but is not modified by classical modifiers of position-effect variegation. Our results, together with the report of a Pc -G binding site in 69D, suggest that we have identified a novel cluster of target genes for the Pc-G and trx-G products. We thus propose that ventral silencing of the whole IRO-C in the eye occurs at the level of chromatin structure in a manner similar to that of the homeotic gene complexes, perhaps by local compaction of the region into a heterochromatin-like structure involving the Pc-G products.



Development ◽  
2010 ◽  
Vol 137 (16) ◽  
pp. 2795-2804 ◽  
Author(s):  
A. Porcher ◽  
A. Abu-Arish ◽  
S. Huart ◽  
B. Roelens ◽  
C. Fradin ◽  
...  




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