Silencing at Drosophila telomeres:: nuclear organization and chromatin structure play critical roles
Silencing at Drosophila telomeres:: nuclear organization and chromatin structure play critical roles
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DOI：
10.1093/emboj/18.13.3724
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发表时间：
1999-07-01
期刊：
影响因子：
11.4
通讯作者：
Wallrath, LL
中科院分区：
文献类型：
--
作者：
Cryderman, DE;Morris, EJ;Wallrath, LL
插入到果蝇染色体端粒区的转基因呈现位置效应变异(PEV)，即常染色质基因与异染色质并列的嵌合体沉默特征，第二和第三染色体上的端粒转基因基因由端粒相关序列(TAS)组成，而第四染色体上的端粒转基因基因最常与重复的转座元件相关。第二和第三染色体上的端粒PEV被SU(Z)2的突变抑制，但不被SU(Var)2-5(编码HP1)的突变所抑制，而第四染色体上的端粒PEV则相反。这种遗传差异允许对端粒PEV进行空间和分子分析。含有转基因的第四染色体端粒区和第二染色体端粒区之间的相互易位导致转基因的核位置发生变化。虽然白色转基因的多样性表型被抑制，但对HP1突变的敏感性仍保持不变。相关的hsp26转基因的染色质结构和诱导活性也发生了相应的变化。这些数据表明，核组织和局部染色质结构在端粒PEV中起着作用。
Transgenes inserted into the telomeric regions of Drosophila melanogaster chromosomes exhibit position effect variegation (PEV), a mosaic silencing characteristic of euchromatic genes brought into juxtaposition with heterochromatin, Telomeric transgenes on the second and third chromosomes are flanked by telomeric associated sequences (TAS), while fourth chromosome telomeric transgenes are most often associated with repetitious transposable elements. Telomeric PEV on the second and third chromosomes is suppressed by mutations in Su(z)2, but not by mutations in Su(var)2-5 (encoding HP1), while the converse is true for telomeric PEV on the fourth chromosome. This genetic distinction allowed for a spatial and molecular analysis of telomeric PEV. Reciprocal translocations between the fourth chromosome telomeric region containing a transgene and a second chromosome telomeric region result in a change in nuclear location of the transgene. While the variegating phenotype of the white transgene is suppressed, sensitivity to a mutation in HP1 is retained. Corresponding changes in the chromatin structure and inducible activity of an associated hsp26 transgene are observed. The data indicate that both nuclear organization and local chromatin structure play a role in this telomeric PEV.