Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA.
Dev Biol. 2010 Apr 15;340(2):528-38. doi: 10.1016/j.ydbio.2010.02.006. Epub 2010 Feb 10.
Localization of the germ plasm to the posterior of the Drosophila oocyte is required for anteroposterior patterning and germ cell development during embryogenesis. While mechanisms governing the localization of individual germ plasm components have been elucidated, the process by which germ plasm assembly is restricted to the posterior pole is poorly understood. In this study, we identify a novel allele of bazooka (baz), the Drosophila homolog of Par-3, which has allowed the analysis of baz function throughout oogenesis. We demonstrate that baz is required for spatial restriction of the germ plasm and axis patterning, and we uncover multiple requirements for baz in regulating the organization of the oocyte microtubule cytoskeleton. Our results suggest that distinct cortical domains established by Par proteins polarize the oocyte through differential effects on microtubule organization. We further show that microtubule plus-end enrichment is sufficient to drive germ plasm assembly even at a distance from the oocyte cortex, suggesting that control of microtubule organization is critical not only for the localization of germ plasm components to the posterior of the oocyte but also for the restriction of germ plasm assembly to the posterior pole.
果蝇卵子后极的生殖质定位对于胚胎发生过程中的前后模式形成和生殖细胞发育是必需的。虽然已经阐明了控制单个生殖质成分定位的机制，但生殖质组装如何被限制在后极的过程还知之甚少。在这项研究中，我们鉴定了 bazooka（baz）的一个新等位基因，它是果蝇 Par-3 的同源物，这使得我们能够在整个卵子发生过程中分析 baz 的功能。我们证明 baz 对于生殖质的空间限制和轴的模式形成是必需的，并且我们发现 baz 在调节卵母细胞微管细胞骨架的组织中有多种作用。我们的结果表明，Par 蛋白建立的不同皮质域通过对微管组织的不同影响来使卵母细胞极化。我们进一步表明，微管正极富集足以驱动生殖质组装，即使在远离卵母细胞皮质的地方，这表明微管组织的控制不仅对生殖质成分定位到卵母细胞的后极很关键，而且对生殖质组装限制在后极也很关键。
