An essential step in muscle fiber maturation is the assembly of highly ordered myofibrils that are required for contraction. Much remains unknown about the molecular mechanisms governing the formation of the contractile apparatus. We identified an early embryonic motility mutant in zebrafish caused by integration of a transgene into the pseudophosphatase dual specificity phosphatase 27 (dusp27) gene. dusp27 mutants exhibit near complete paralysis at embryonic and larval stages, producing extremely low levels of spontaneous coiling movements and a greatly diminished touch response. Loss of dusp27 does not prevent somitogenesis but results in severe disorganization of the contractile apparatus in muscle fibers. Sarcomeric structures in mutants are almost entirely absent and only rare triads are observed. These findings are the first to implicate a functional role of dusp27 as a gene required for myofiber maturation and provide an animal model for analyzing the mechanisms governing myofibril assembly.
The authors declare no competing financial interests.
K.F., S.A.B., E.J.H., J.J.D., F.O. and H.A.B. conceived and designed the experiments. K.F., G.H.L., H.C., S.A.B., E.J.H., H.A.B. and F.O. performed the experiments. S.A.B., J.J.D., F.O. and H.A.B. analyzed the data. H.A.B. wrote the draft and all authors contributed to the final manuscript.
This work was supported by the Intramural Research Programs of the NICHD (H.A.B.) and of the NIAAA (F.O.), and National Institutes of Health grants 1K08AR054835 (J.J.D.) and T32 NS007222 (E.J.H.).
Supplementary material available online at http://dmm.biologists.org/lookup/suppl/doi:10.1242/dmm.013235/-/DC1
- Received June 6, 2013.
- Accepted November 4, 2013.
- © 2014. Published by The Company of Biologists Ltd
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution and reproduction in any medium provided that the original work is properly attributed.