Karr T L, Ali Z, Drees B, Kornberg T
Cell. 1985 Dec;43(3 Pt 2):591-601. doi: 10.1016/0092-8674(85)90231-4.
Early embryonic development in Drosophila depends on genes expressed during oogenesis or after zygote formation. We show that the engrailed gene is needed for the processes that organize the embryo during the nuclear divisions that precede cellularization. During the precellular blastoderm stages engrailed mutant embryos show several notable anomalies: the pole cells form at a position slightly displaced from the posterior pole; yolk nuclei continue to divide after the tenth nuclear division cycle, when wild-type yolk nuclei have stopped dividing mitotically; and somatic nuclei are not positioned uniformly along the embryo periphery and do not undergo mitotic divisions in regular waves. This early requirement for engrailed does not appear to be a maternal function, and only genetically engrailed embryos displayed these precellular phenotypes. Synthesis of a 2.7 kb poly(A)+ transcript of the engrailed region was found in precellular embryos.
果蝇的早期胚胎发育依赖于卵子发生过程中或合子形成后表达的基因。我们发现，在细胞化之前的核分裂过程中， engrailed基因对于胚胎组织过程是必需的。在细胞化前的囊胚阶段， engrailed突变体胚胎表现出几个显著的异常现象：极细胞在偏离后极的位置形成；当野生型卵黄核停止有丝分裂时， engrailed突变体胚胎的卵黄核在第十个核分裂周期后仍继续分裂；并且体细胞的细胞核没有沿胚胎周边均匀定位，也没有以规则的波状进行有丝分裂。 engrailed基因的这种早期需求似乎不是母源功能，只有遗传上携带 engrailed突变的胚胎才表现出这些细胞化前的表型。在细胞化前的胚胎中发现了 engrailed区域的一个2.7 kb的聚腺苷酸化转录本。
