ZFIN ID: ZDB-PUB-090417-4
Heterochronic shift in Hox-mediated activation of sonic hedgehog leads to morphological changes during fin development
Sakamoto, K., Onimaru, K., Munakata, K., Suda, N., Tamura, M., Ochi, H., and Tanaka, M.
Date: 2009
Source: PLoS One 4(4): e5121 (Journal)
Registered Authors: Ochi, Haruki, Tanaka, Mikiko
Keywords: Embryos, Zebrafish, Limb buds, Dogfish, Messenger RNA, Hedgehog signaling, Gene expression, Vertebrates
MeSH Terms: Animals; Biological Evolution; Body Patterning/physiology; Dogfish/anatomy & histology; Dogfish/embryology* (all 24) expand
PubMed: 19365553 Full text @ PLoS One
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ABSTRACT
We explored the molecular mechanisms of morphological transformations of vertebrate paired fin/limb evolution by comparative gene expression profiling and functional analyses. In this study, we focused on the temporal differences of the onset of Sonic hedgehog (Shh) expression in paired appendages among different vertebrates. In limb buds of chick and mouse, Shh expression is activated as soon as there is a morphological bud, concomitant with Hoxd10 expression. In dogfish (Scyliorhinus canicula), however, we found that Shh was transcribed late in fin development, concomitant with Hoxd13 expression. We utilized zebrafish as a model to determine whether quantitative changes in hox expression alter the timing of shh expression in pectoral fins of zebrafish embryos. We found that the temporal shift of Shh activity altered the size of endoskeletal elements in paired fins of zebrafish and dogfish. Thus, a threshold level of hox expression determines the onset of shh expression, and the subsequent heterochronic shift of Shh activity can affect the size of the fin endoskeleton. This process may have facilitated major morphological changes in paired appendages during vertebrate limb evolution.
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