Seum C, Spierer A, Pauli D, Szidonya J, Reuter G, Spierer P
Department of Zoology and Animal Biology, University of Geneva, Switzerland.
Development. 1996 Jun;122(6):1949-56. doi: 10.1242/dev.122.6.1949.
A dominant mutation due to the insertion of a P-element at 93E on the third chromosome of Drosophila melanogaster enhances position-effect variegation. The corresponding gene was cloned by transposon tagging and the sequence of the transcript revealed that it corresponds to the gene encoding the transcriptional activator and cell cycle regulator dE2F. The transposon-tagged allele is homozygous viable, and the insertion of the transposon in an intron correlates with a strong reduction in the amount of transcript. A homozygous lethal null allele was found to behave as a strong enhancer when heterozygous. Overexpression of the gene in transgenic flies has the opposite effect of suppressing variegation. A link is established here, and discussed, between the dose of a transcriptional activator, which controls the cell cycle, and epigenetic silencing of chromosomal domains in Drosophila.
由于在黑腹果蝇第三条染色体93E位置插入一个P因子而导致的显性突变增强了位置效应斑驳。通过转座子标签法克隆了相应基因，转录本序列显示它对应于编码转录激活因子和细胞周期调节因子dE2F的基因。转座子标签等位基因纯合时可存活，转座子插入内含子与转录本数量的大幅减少相关。发现一个纯合致死无效等位基因在杂合时表现为强增强子。该基因在转基因果蝇中的过表达具有抑制斑驳的相反作用。本文建立并讨论了控制细胞周期的转录激活因子剂量与果蝇染色体结构域表观遗传沉默之间的联系。
