The promoter of the heterochromatic Drosophila telomeric retrotransposon, HeT-A, is active when moved into euchromatic locations.
The promoter of the heterochromatic Drosophila telomeric retrotransposon, HeT-A, is active when moved into euchromatic locations.
复制标题
异染色质果蝇端粒逆转录转座子 HeT-A 的启动子在移动到常染色质位置时具有活性。
DOI：
10.1093/genetics/163.2.625
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发表时间：
2003
期刊：
影响因子：
3.3
通讯作者：
Pardue,Mary-Lou
中科院分区：
文献类型：
--
作者：
George,JanetA;Pardue,Mary-Lou
果蝇端粒逆转录转座子HeT-A仅存在于异染色质中，因此其启动子必须在异染色质环境中发挥作用。位置效应杂色的研究表明，异染色质基因的启动子是非常不同的常染色质启动子，但这个想法还没有被测试与孤立的启动子序列。TheHeT-A启动子是第一个被分离的异染色质启动子，当从端粒异染色质中去除时，研究其活性是有意义的。该启动子最初通过在培养细胞的瞬时转染中测试报告构建体来表征，所述培养细胞的环境可能接近其内源性异染色质。我们现在报告P-元件介导的这些结构的转座，在常染色质中测试推定的启动子的不同部分的功能。内源性HeT-ARNA的表达表现出明显的发育调节和积累优先在复制二倍体tissues. HeT-A启动子结构是活跃的，在所有常染色质的位置测试和一些显示方面的内源性HeT-A阶段和细胞类型的表达程序。每个启动子构建体在常染色质位置的活性通常也与其在瞬时转染试验中的活性一致;一个可能显著的例外是一个序列片段，其在瞬时转染中明显增强活性，但在常染色质中抑制启动子活性。
The Drosophila telomeric retrotransposon,HeT-A, is found only in heterochromatin; therefore, its promoter must function in this chromatin environment. Studies of position effect variegation suggest that promoters of heterochromatic genes are very different from euchromatic promoters, but this idea has not been tested with isolated promoter sequences. TheHeT-Apromoter is the first heterochromatin promoter to be isolated and it is of interest to investigate its activity when removed from telomeric heterochromatin. This promoter was initially characterized by testing reporter constructs in transient transfection of cultured cells, an environment that may approximate its endogenous heterochromatin. We now reportP-element-mediated transpositions of these constructs, testing the function of different parts of the putative promoter in euchromatin. Expression of endogenousHeT-ARNA shows marked developmental regulation and accumulates preferentially in replicating diploid tissues.HeT-Apromoter constructs are active in all euchromatic locations tested and some display aspects of endogenousHeT-Astage- and cell-type expression programs. The activity of each promoter construct in euchromatic locations is also generally consistent with its activity in the transient transfection tests; a possibly significant exception is one sequence segment that appreciably enhanced activity in transient transfection but repressed promoter activity in euchromatin.