Institute of Biological Sciences, University of Tsukuba, Sakura-mura, Ibaraki 305, Japan.
Proc Natl Acad Sci U S A. 1982 Nov;79(22):6946-50. doi: 10.1073/pnas.79.22.6946.
A subcellular fraction isolated from a homogenate of young Drosophila embryos was shown to be capable of inducing pole cells when injected into UV-sterilized Drosophila embryos. Most of the pole cell-inducing activity was recovered from the precipitate after centrifugation at 27,000 x g. The activity remained in this precipitate (called F-3 fraction hereafter) even after membranous structures were removed from it through centrifugation on a sucrose density gradient. Dialysis, lyophilization, and heating at 80 degrees C for 10 min did not inactivate the F-3 fraction. The pole cells, which were produced when the F-3 fraction was injected at the posterior pole of UV-sterilized embryos, did not develop into germ cells. Furthermore, the F-3 fraction was unable to induce pole cells when injected into the anterior region of the egg. These results can be explained by assuming that (i) pole cell formation and germ cell determination are controlled by different factors, (ii) pole cell formation requires at least two factors, which are normally localized in the posterior-pole cytoplasm, one of which is sensitive and one resistant to the UV dosage we used, and (iii) the subcellular fraction we obtained contains the UV-sensitive factor but not the UV-resistant factor.
从年轻果蝇胚胎匀浆中分离出的亚细胞级分被证明能够在注射到紫外线灭菌的果蝇胚胎中诱导极细胞。大多数极细胞诱导活性从 27000xg 离心后的沉淀物中回收。即使通过在蔗糖密度梯度上离心去除膜结构，该活性仍保留在该沉淀物中（以下称为 F-3 级分）。透析、冻干和在 80°C 加热 10 分钟不会使 F-3 级分失活。当将 F-3 级分注射到紫外线灭菌胚胎的后极时，产生的极细胞不会发育成生殖细胞。此外，当将 F-3 级分注射到卵的前区域时，它不能诱导极细胞。这些结果可以通过以下假设来解释：（i）极细胞形成和生殖细胞决定由不同的因素控制，（ii）极细胞形成至少需要两种因子，这些因子通常位于后极细胞质中，其中一种对我们使用的紫外线剂量敏感，另一种则有抗性，（iii）我们获得的亚细胞级分包含紫外线敏感因子而不包含紫外线抗性因子。
