THE GNU MUTATION OF DROSOPHILA CAUSES INAPPROPRIATE DNA-SYNTHESIS IN UNFERTILIZED AND FERTILIZED-EGGS
THE GNU MUTATION OF DROSOPHILA CAUSES INAPPROPRIATE DNA-SYNTHESIS IN UNFERTILIZED AND FERTILIZED-EGGS
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DOI：
10.1101/gad.1.9.924
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发表时间：
1987-11-01
影响因子：
10.5
通讯作者：
GLOVER, DM
中科院分区：
文献类型：
--
作者：
FREEMAN, M;GLOVER, DM
母鼠纯合子致死突变gnu的黑腹果蝇胚胎（gnu胚胎），DNA合成但无核分裂；这导致在合胞胚层中形成少量的巨核。我们之前已经表明，有丝分裂装置的许多组成部分在GNU胚胎中存在并起作用，因此GNU突变的主要病变仍然不清楚。在这里，我们报告了受精对GNU卵子的发育是不必要的。巨大的细胞核起源于雌性减数分裂的产物，我们看到自主复制的中心体必须来自母体。然而，如果GNU卵子是人工授精的，那么雄性原核也会进行DNA复制。我们的观察表明，GNU细胞质允许DNA合成在一个相对不受管制的方式。在雌性纯合的gnu和雌性不育单倍体突变的mh的胚胎中，我们发现来自雄性原核的DNA复制。这与母亲纯合子的胚胎形成对比，在纯合子中不会发生这种情况。我们提出gnu基因产物参与抑制未受精卵中发现的DNA合成。
Drosophila melanogaster embryos whose mothers are homozygous for the maternal effect lethal mutation gnu (GNU embryos) under DNA synthesis but no nuclear division; this leads to the formation of a small number of giant nuclei in the syncytial blastoderm. We have shown previously that many components of the mitotic apparatus are present and functional in GNU embryos, and the primary lesion of the gnu mutation has therefore remained obscure. Here, we report that fertilization is not necessary for GNU eggs to develop. Giant nuclei originate from the products of female meiosis, and we see autonomously replicating centrosomes that must be maternally derived. If GNU eggs are inseminated, however, the male pronucleus also undergoes DNA replication. Our observations suggest that the GNU cytoplasm permits DNA synthesis in a relatively unregulated manner. In embryos from females homozygous for gnu and the female sterile haploid mutation mh, we find replication of DNA derived from the male pronucleus. This contrasts with embryos from mothers homozygous for mh alone, in which this does not occur. We propose that the gnu gene product participates in the repression of DNA synthesis found in unfertilized eggs.