In some cases, gene transfer from euchromatin to constitutive heterochromatin as a result of chromosomal rearrangement is accompanied by epigenetic inactivation of this gene (cis-inactivation). In the case of trans-inactivation, transgenes in the normal chromosome are repressed by the cis-inactivation-causing rearranged homologous chromosome. Trans-inactivation is a result of the somatic pairing of homologs and the transfer of the normal chromosomal segment to the heterochromatic compartment of the nucleus. Previously, we have shown that the degree of trans-inactivation of the UAS-eGFP reporter gene in adult flies depends on its transcription level that can be regulated by temperature using the GAL4 transcription activator and its temperature-sensitive inhibitor GAL80ts. In this paper, we investigated the epigenetic inheritance of the active/repressed state of the trans-inactivated reporter gene at different expression levels by measuring eGFP fluorescence in the individual cells of Malpighian tubules in adult flies. High expression levels at the embryonic stage protected the eGFP gene from trans-inactivation in adult flies. The activated state was inherited over the entire period of development and differentiation, while the activating effect of GAL4 was turned off.

中文翻译：

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胚胎阶段的高水平基因转录导致黑腹果蝇成虫异色反式失活的抑制

在某些情况下，由于染色体重排，基因从常染色质转移到组成型异染色质伴随着该基因的表观遗传失活（顺式失活）。在反式失活的情况下，正常染色体中的转基因被导致顺式失活的重排同源染色体抑制。反式失活是同源物的体细胞配对和正常染色体片段转移到细胞核的异色区室的结果。以前，我们已经表明，成年果蝇中 UAS-eGFP 报告基因的反式失活程度取决于其转录水平，可以使用 GAL4 转录激活剂及其温度敏感抑制剂 GAL80ts 来调节温度。在本文中，我们通过测量成年果蝇马氏小管单个细胞中的 eGFP 荧光，研究了不同表达水平下反式失活报告基因的活性/抑制状态的表观遗传。胚胎阶段的高表达水平保护了 eGFP 基因在成年果蝇中免于反式失活。激活状态在整个发育和分化时期被继承，而GAL4的激活作用被关闭。