Transcriptional silencing of Ty1 elements in the RDN1 locus of yeast
Transcriptional silencing of Ty1 elements in the RDN1 locus of yeast
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DOI：
10.1101/gad.11.2.255
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发表时间：
1997-01-15
影响因子：
10.5
通讯作者：
Curcio, MJ
中科院分区：
文献类型：
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作者：
Bryk, M;Banerjee, M;Curcio, MJ
我们证明，在酿酒酵母中，核糖体RNA基因（RDN 1）的串联阵列是一个目标的Ty 1逆转录转座子，导致沉默的Ty 1转录和转座的整合。Ty 1元件转座成随机rDNA重复单元，并且在有丝分裂中稳定。此外，我们已经发现，RDN 1染色质结构的几个假定的修饰剂的突变废除了沉默的rDNA阵列中的Ty 1元件。SIR 2的破坏，其提高了RDN 1中的重组，或TOP1，其增加了rDNA中的蛋白酶可及性，或HTA 1-HTB 1，其降低了组蛋白H2 A-H2 B水平并引起局部染色质扰动，消除了RDN 1中Ty 1元件的转录沉默。此外，泛素结合酶Ubc 2 p，在体外泛素化组蛋白的基因的缺失，不仅Ty 1转录，而且RDN 1有丝分裂重组的解抑制。在这些结果的基础上，我们提出，一个专门的染色质结构存在于RDN 1沉默转录的Ty 1反转录转座子。
We demonstrate that in Saccharomyces cerevisiae, the tandem array of ribosomal RNA genes (RDN1) is a target for integration of the Ty1 retrotransposon that results in silencing of Ty1 transcription and transposition. Ty1 elements transpose into random rDNA repeat units and are mitotically stable. In addition, we have found that mutation of several putative modifiers of RDN1 chromatin structure abolishes silencing of Ty1 elements in the rDNA array. Disruption of SIR2, which elevates recombination in RDN1, or TOP1, which increases psoralen accessibility in rDNA, or HTA1-HTB1, which reduces histone H2A-H2B levels and causes localized chromatin perturbations, abolishes transcriptional silencing of Ty1 elements in RDN1. Furthermore, deletion of the gene for the ubiquitin conjugating enzyme Ubc2p, which ubiquitinates histones in vitro, derepresses not only Ty1 transcription but also mitotic recombination in RDN1. On the basis of these results, we propose that a specialized chromatin structure exists in RDN1 that silences transcription of the Ty1 retrotransposon.