γ-Tubulin small complex formation is essential for early zebrafish embryogenesis

Abstract

© 2018 The centrosomal protein γ-tubulin is part of the cytoplasmic γ-tubulin small (γ-TuSCs) and large complexes (γ-TuRCs). Both, molecular and cellular evidence indicate that γ-tubulin plays a central role in microtubule nucleation and mitotic spindle formation. However, the molecular mechanisms of complex formation and subsequent biological roles in animal development remain unclear. Here, we used γ-tubulin gene knockdown in the zebrafish early embryo model to gain insights into its activity and cellular contribution during vertebrate embryogenesis. γ-Tubulin loss-of-function impaired γ-TuSC formation, impacting the microtubule nucleation rate in vitro. Moreover, decreased γ-tubulin synthesis caused dramatic defects in nuclear dynamics and cell cycle progression, leading to developmental arrest at the mid-gastrula stage. At the subcellular level, microtubule organization and function were altered, affecting chromosome segregation and triggering cell proliferation arrest and apoptosi