Bouldin, C.M., Snelson, C.D., Farr, G.H. 3rd, and Kimelman, D. (2014) Restricted expression of cdc25a in the tailbud is essential for formation of the zebrafish posterior body. Genes & Development. 28(4):384-95.
The vertebrate body forms from a multipotent stem cell-like progenitor population that progressively contributes newly differentiated
cells to the most posterior end of the embryo. How the progenitor population balances proliferation and other cellular functions
is unknown due to the difficulty of analyzing cell division in vivo. Here, we show that proliferation is compartmentalized
at the posterior end of the embryo during early zebrafish development by the regulated expression of cdc25a, a key controller of mitotic entry. Through the use of a transgenic line that misexpresses cdc25a, we show that this compartmentalization is critical for the formation of the posterior body. Upon misexpression of cdc25a, several essential T-box transcription factors are abnormally expressed, including Spadetail/Tbx16, which specifically prevents
the normal onset of myoD transcription, leading to aberrant muscle formation. Our results demonstrate that compartmentalization of proliferation during
early embryogenesis is critical for both extension of the vertebrate body and differentiation of the multipotent posterior
progenitor cells to the muscle cell fate.