1. The B-cell maturation factor Blimp-1 specifies vertebrate slow-twitch muscle fiber identity in response to Hedgehog signaling.
- Author
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Baxendale, Sarah, Davison, Claire, Muxworthy, Claire, Wolff, Christian, Roy, Sudipto, and Ingham, Philip W.
- Subjects
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MUSCLES , *PROMOTERS (Genetics) , *TRANSCRIPTION factors , *MYOBLASTS , *ANIMAL mutation - Abstract
Vertebrate skeletal muscles comprise distinct fiber types that differ in their morphology, contractile function, mitochondrial content and metabolic properties. Recent studies identified the transcriptional coactivator PGC-1a as a key mediator of the physiological stimuli that modulate fiber-type plasticity in postembryonic development. Although myoblasts become fated to differentiate into distinct kinds of fibers early in development, the identities of regulatory proteins that determine embryonic fiber-type specification are still obscure. Here we show that the gene u-boot (ubo), a mutation in which disrupts the induction of embryonic slow-twitch fibers, encodes the zebrafish homolog of Blimp-1, a SET domain-containing transcription factor that promotes the terminal differentiation of B lymphocytes in mammals. Expression of ubo is induced by Hedgehog (Hh) signaling in prospective slow muscle precursors, and its activity alone is sufficient to direct slow-twitch fiber-specific development by naive myoblasts. Our data provide the first molecular insight into the mechanism by which a specific group of muscle precursors is driven along a distinct pathway of fiber-type differentiation in response to positional cues in the vertebrate embryo. [ABSTRACT FROM AUTHOR]
- Published
- 2004
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