Nuclear shape and size vary between species, during development, and in many tissue pathologies, but the causes and effects of these differences remain poorly understood. During fertilization, sperm nuclei undergo a dramatic conversion from a heavily compacted form into decondensed, spherical pronuclei, accompanied by rapid nucleation of microtubules from centrosomes. Here we report that the assembly of the spherical nucleus depends on a critical balance of microtubule dynamics, which is regulated by the chromatin-binding protein Developmental pluripotency-associated 2 (Dppa2). Whereas microtubules normally promote sperm pronuclear expansion, in Dppa2-depleted Xenopus egg extracts excess microtubules cause pronuclear assembly defects, leading to abnormal morphology and disorganized DNA replication. Dppa2 inhibits microtubule polymerization invitro, and Dppa2 activity is needed at a precise time and location during nascent pronuclear formation. This demonstrates a strict spatiotemporal requirement for local suppression of microtubules during nuclear formation, fulfilled by chromatin-bound microtubule regulators. © 2013 Elsevier Inc.
Xue, J. Z., Woo, E. M., Postow, L., Chait, B. T., & Funabiki, H. (2013). Chromatin-Bound Xenopus Dppa2 Shapes the Nucleus by Locally Inhibiting Microtubule Assembly. Developmental Cell, 27(1), 47–59. https://doi.org/10.1016/j.devcel.2013.08.002