Laboratoire de Génétique Moléculaire des Eucaryotes du CNRS, Unité 184 de Biologie Moléculaire et de Génie Génétique de l'INSERM, Faculté de Médecine, 67085 Strasbourg Cédex, France.
Genetics. 1983 Nov;105(3):615-32. doi: 10.1093/genetics/105.3.615.
Maternal-zygotic interactions involving the three genes dorsal (dl), twist (twi) and snail (sna) are described. The results suggest that all three are involved in the process by which the dorsoventral pattern of the Drosophila embryo is established. First, the lethal embryonic mutant phenotypes are rather similar. In homozygous twi or sna embryos invagination of the ventral presumptive mesodermal cells fails to occur, and the resulting embryos are devoid of internal organs. This is very similar to the dominant phenotype described for dl; in the case of dl, however, the effect is a maternal one dependent on the mutant genotype of the female. Second, a synergistic interaction has been found whereby dominant lethality of twi- or sna-bearing zygotes is observed in embryos derived from heterozygous dl females at high temperature. The temperature sensitivity of this interaction permitted definition of a temperature-sensitive period which is probably that of dl. This was found to extend from approximately 12 hr prior to oviposition to 2-3 hr of embryogenesis. A zygotic action for the dl gene in addition to the maternal effect was revealed by the finding that extra doses of dl(+) in the zygotes can partially rescue the dominant lethality of heterozygous twi embryos derived from heterozygous dl females. Two possible interpretations of the synergism are considered: (1) twi and sna are activated in the embryos as a result of positional signals placed in the egg as a consequence of the functioning of the dl gene during oogenesis and, thus, play a role in embryonic determination. (2) The gene products of dl(+) and twi (+) (or sna(+)) combine to produce a functional molecule that is involved in the specification of dorsoventral pattern in the early embryo.
描述了涉及三个基因 dorsal（dl）、twist（twi）和 snail（sna）的母体-合子相互作用。结果表明，这三个基因都参与了果蝇胚胎背腹模式的建立过程。首先，致死性胚胎突变体表型非常相似。在纯合 twi 或 sna 胚胎中，腹侧前体细胞的内陷未能发生，导致胚胎缺乏内部器官。这与 dl 描述的显性表型非常相似；然而，在 dl 的情况下，这种效应是母体依赖的，取决于雌性的突变基因型。其次，发现了一种协同作用，即在高温下，来自杂合 dl 雌性的胚胎中存在 twi 或 sna 携带的合子的显性致死性。这种相互作用的温度敏感性允许定义一个可能是 dl 的温度敏感期。发现这个时期从产卵前大约 12 小时延伸到胚胎发生的 2-3 小时。除了母体效应之外，dl 基因在合子中也有作用，这是通过发现额外剂量的 dl(+)可以部分挽救来自杂合 dl 雌性的杂合 twi 胚胎的显性致死性这一发现揭示的。对协同作用有两种可能的解释：（1）twi 和 sna 在胚胎中被激活，是由于 dl 基因在卵子发生过程中的功能导致卵子中产生位置信号的结果，因此，在胚胎决定中发挥作用。（2）dl(+)和 twi (+)（或 sna(+))的基因产物结合产生一种功能性分子，参与早期胚胎背腹模式的指定。
