Boswell R E, Prout M E, Steichen J C
Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder 80309-0347.
Development. 1991 Sep;113(1):373-84. doi: 10.1242/dev.113.1.373.
The mago nashi (mago) locus is a newly identified strict maternal effect, grandchildless-like, gene in Drosophila melanogaster. In homozygous mutant mago females reared at 17 degrees C, mago+ function is reduced, the inviable embryos lack abdominal segments and 84-98% of the embryos die. In contrast, at 25 degrees C, some mago alleles produce a novel gene product capable of inducing the formation of symmetrical double abdomen embryos. Reciprocal temperature-shift experiments indicate that the temperature-sensitive period is during oogenetic stages 7-14. Furthermore, embryos collected from mago1 homozygous females contain no apparent functional posterior determinants in the posterior pole. In viable F1 progeny from mago mutant females, regardless of genotype and temperature, polar granules are reduced or absent and germ cells fail to form (the grandchildless-like phenotype). Thus, we propose that the mago+ product is a component of the posterior determinative system, required during oogenesis, both for germ cell determination and delineation of the longitudinal axis of the embryo.
无后（mago）基因座是在黑腹果蝇中新鉴定出的一个严格的母性效应、类似无孙代的基因。在17摄氏度饲养的纯合突变体mago雌性果蝇中，mago+功能降低，无法存活的胚胎缺少腹部节段，84% - 98%的胚胎死亡。相比之下，在25摄氏度时，一些mago等位基因产生一种新型基因产物，能够诱导形成对称的双腹胚胎。相互温度转换实验表明，温度敏感期在卵子发生的7 - 14阶段。此外，从mago1纯合雌性果蝇收集的胚胎在后极没有明显的功能性后决定因子。在mago突变体雌性果蝇的可存活F1后代中，无论基因型和温度如何，极颗粒减少或缺失，生殖细胞无法形成（类似无孙代的表型）。因此，我们提出mago+产物是后决定系统的一个组成部分，在卵子发生过程中是生殖细胞决定和胚胎纵轴划定所必需的。
