mariette-cooptionofthecardiac-2017.pdf (3.26 MB)
Co-option of the cardiac transcription factor Nkx2.5 during development of the emu wing
journal contribution
posted on 2017-07-25, 00:00 authored by P G Farlie, N M Davidson, N L Baker, M Raabus, K N Roeszler, C Hirst, A Major, Mylene MarietteMylene Mariette, D M Lambert, A Oshlack, C A SmithThe ratites are a distinctive clade of flightless birds, typified by the emu and ostrich that have acquired a range of unique anatomical characteristics since diverging from basal Aves at least 100 million years ago. The emu possesses a vestigial wing with a single digit and greatly reduced forelimb musculature. However, the embryological basis of wing reduction and other anatomical changes associated with loss of flight are unclear. Here we report a previously unknown co-option of the cardiac transcription factor Nkx2.5 to the forelimb in the emu embryo, but not in ostrich, or chicken and zebra finch, which have fully developed wings. Nkx2.5 is expressed in emu limb bud mesenchyme and maturing wing muscle, and mis-expression of Nkx2.5 throughout the limb bud in chick results in wing reductions. We propose that Nkx2.5 functions to inhibit early limb bud expansion and later muscle growth during development of the vestigial emu wing.The transcription factor Nkx2.5 is essential for heart development. Here, the authors identify a previously unknown expression domain for Nkx2.5 in the emu wing and explore its role in diminished wing bud development in the flightless emu, compared with three other birds that have functional wings.
History
Journal
Nature communicationsVolume
8Article number
132Pagination
1 - 12Publisher
Nature Publishing GroupLocation
London, Eng.Publisher DOI
ISSN
2041-1723eISSN
2041-1723Language
engPublication classification
C Journal article; C1 Refereed article in a scholarly journalCopyright notice
2017, The AuthorsUsage metrics
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