Torpey N, Wylie C C, Heasman J
Wellcome/Cancer Research Campaign Institute of Cancer, Cambridge, UK.
Nature. 1992 Jun 4;357(6377):413-5. doi: 10.1038/357413a0.
Intermediate filaments are ubiquitous in eukaryotic cells, but their functions are poorly understood. The Xenopus oocyte contains both messenger RNA and protein products of cytokeratin and vimentin genes in non-overlapping arrays. The cytokeratin filaments contain dimers of the type I (acidic) subunit XLK3a(19), and the type II (basic) subunit XCK1(8), polymerized to form a cortical network. These are homologues of the human simple epithelial keratins 19 and 8, respectively. After the first few cell cycles following fertilization these filaments become restricted to the superficial cells of the blastula. We have depleted the oocyte's store of the type II cytokeratin mRNA by injecting antisense oligodeoxynucleotides (oligos) and studied the effect on embryonic development. As zygotic transcription does not commence until the late blastula stage, there are at least 9 hours in which to see the effect of loss of function of this mRNA. We report here that the cytokeratin filaments become depleted in the cortical cells of the embryo. As a result, there is a loss of the 'compacted' epithelial surface of the blastula, an inability to close a wounded surface and defective gastrulation.
中间丝在真核细胞中普遍存在，但其功能却鲜为人知。非洲爪蟾卵母细胞含有细胞角蛋白和波形蛋白基因的信使核糖核酸及蛋白质产物，它们呈非重叠排列。细胞角蛋白丝由I型（酸性）亚基XLK3a(19)和II型（碱性）亚基XCK1(8)的二聚体聚合形成皮质网络。它们分别是人类简单上皮角蛋白19和8的同源物。受精后的最初几个细胞周期后，这些丝状体局限于囊胚的表层细胞。我们通过注射反义寡脱氧核苷酸（寡核苷酸）耗尽了卵母细胞中II型细胞角蛋白信使核糖核酸的储备，并研究了其对胚胎发育的影响。由于合子转录直到囊胚后期才开始，所以至少有9个小时可以观察到这种信使核糖核酸功能丧失的影响。我们在此报告，胚胎皮质细胞中的细胞角蛋白丝减少。结果，囊胚“紧密”的上皮表面消失，无法闭合受伤表面，并且原肠胚形成存在缺陷。
