Pondel M D, King M L
Department of Anatomy and Cell Biology, University of Virginia School of Medicine, Charlottesville 22908.
Proc Natl Acad Sci U S A. 1988 Oct;85(20):7612-6. doi: 10.1073/pnas.85.20.7612.
The localized maternal RNA Vg1 resides in the cortical region of the vegetal pole of fully grown Xenopus oocytes and is inherited by only a subset of blastomeres in the early embryo [Weeks, D. L. & Melton, D. A. (1987) Cell 51, 861-867]. Because RNA-cytoskeletal interactions may play a role in RNA localization, we have examined the association of Vg1 RNA with components of the oocyte's cytoskeleton. Gel and immunoblot analysis of a detergent-insoluble fraction revealed a greatly simplified protein pattern composed largely of cytokeratins and vimentin. In sharp contrast to the nonlocalized histone H3 mRNA, Vg1 RNA was concentrated some 35- to 50-fold in this insoluble fraction. Extractions at higher salt concentrations yielded preparations further enriched in cytokeratins and in the Vg1 RNA. Upon ovulation, VG1 RNA is released into the soluble fraction. This change in Vg1 RNA distribution coincides with the observed breakdown of cortical cytokeratin filaments [Klymkowsky, M. W., Maynell, L. A. & Polson, A. G. (1987) Development 100, 543-557] and the loss of Vg1 RNA from the cortical region. Our findings are consistent with the hypothesis that RNA-cytoskeletal interactions are involved in the localization and segregation of information during development.
局部化的母体RNA Vg1存在于完全成熟的非洲爪蟾卵母细胞植物极的皮质区域，并且仅由早期胚胎中的一部分卵裂球继承[威克斯，D. L. & 梅尔顿，D. A.（1987年）《细胞》51卷，861 - 867页]。由于RNA与细胞骨架的相互作用可能在RNA定位中发挥作用，我们研究了Vg1 RNA与卵母细胞细胞骨架成分的关联。对去污剂不溶性部分的凝胶和免疫印迹分析显示，蛋白质模式大大简化，主要由细胞角蛋白和波形蛋白组成。与非局部化的组蛋白H3 mRNA形成鲜明对比的是，Vg1 RNA在该不溶性部分中浓缩了约35至50倍。在更高盐浓度下的提取得到了进一步富含细胞角蛋白和Vg1 RNA的制剂。排卵时，VG1 RNA释放到可溶性部分中。Vg1 RNA分布的这种变化与观察到的皮质细胞角蛋白丝的解体[克莱姆科夫斯基，M. W.，梅内尔，L. A. & 波尔森，A. G.（1987年）《发育》100卷，543 - 557页]以及Vg1 RNA从皮质区域的丢失相一致。我们的发现与RNA - 细胞骨架相互作用参与发育过程中信息的定位和分离这一假设一致。
