A role for TFIIIC transcription factor complex in genome organization
A role for TFIIIC transcription factor complex in genome organization
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DOI：
10.1016/j.cell.2006.04.028
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发表时间：
2006-06-02
期刊：
影响因子：
64.5
通讯作者：
Grewal, Shiv I. S.
中科院分区：
文献类型：
--
作者：
Noma, Ken-ichi;Cam, Hugh P.;Grewal, Shiv I. S.
真核基因组的复杂性需要边界和绝缘子元件将基因组内容划分为不同的域。我们发现，反向重复序列（IR）边界元件侧翼的裂变酵母交配型异染色质结构域包含B盒序列，它防止异染色质扩散到邻近的常染色质区招募转录因子TFIIIC复合物没有RNA聚合酶III（Pol III）。全基因组分析显示TFIIIC与Pol III在所有tRNA基因，其中许多集群在着丝粒周围异染色质域边界。然而，具有适度TFIIIC富集的单个tRNA（phe）基因不足以充当边界，并且需要RNAi相关元件来抑制异染色质扩散。值得注意的是，我们发现TFIIIC本地化没有Pol III在许多网站位于不同的启动子之间。这些位点似乎通过将远处的位点束缚到核外围而充当染色体组织钳，在核外围，TFIIIC：被集中成几个不同的体。我们的分析揭示了一个一般的基因组组织机制，涉及保守的TFIIIC复合物。
Eukaryotic genome complexity necessitates boundary and insulator elements to partition genomic content into distinct domains. We show that inverted repeat (IR) boundary elements flanking the fission yeast mating-type heterochromatin domain contain B-box sequences, which prevent heterochromatin from spreading into neighboring euchromatic regions by recruiting transcription factor TFIIIC complex without RNA polymerase III (Pol III). Genome-wide analysis reveals TFIIIC with Pol III at all tRNA genes, many of which cluster at pericentromeric heterochromatin domain boundaries. However, a single tRNA(phe), gene with modest TFIIIC enrichment is insufficient to serve as boundary and requires RNAi-associated element to restrain heterochromatin spreading. Remarkably, we found TFIIIC localization without Pol III at many sites located between divergent promoters. These sites appear to act as chromosome-organizing clamps by tethering distant loci to the nuclear periphery, at which TFIIIC: is concentrated into several distinct bodies. Our analyses uncover a general genome organization mechanism involving conserved TFIIIC complex.