Changes in chromatin structure correlate with transcriptional activity of nucleolar rDNA in polytene chromosomes.
Changes in chromatin structure correlate with transcriptional activity of nucleolar rDNA in polytene chromosomes.
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染色质结构的变化与多线染色体中核仁 rDNA 的转录活性相关。
DOI：
10.1007/s00412-008-0198-9
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发表时间：
2009
期刊：
影响因子：
1.6
通讯作者：
Labrador,Mariano
中科院分区：
文献类型：
--
作者：
Plata,MariaPiedad;Kang,HyuckJoon;Zhang,Shaofei;Kuruganti,Srilalitha;Hsu,Shih-Jui;Labrador,Mariano
核糖体DNA基因（rDNA）被发现在串联阵列的数百个重复的基因，但只有一小部分的这些基因是活跃的转录。在高等真核生物中，控制活性和非活性rDNA之间转换的调节机制对细胞存活至关重要。在这里，我们表明，核仁从果蝇唾液腺细胞包含两个层次的染色质组织反映转录活性的差异：去凝聚的染色质是高度占用TATA盒结合蛋白（TBP），磷酸化H3S10，乙酰化H3K14，这表明在去凝聚的核仁区域的rDNA是积极转录。浓缩的染色质缺乏TBP、磷酸化的H3S10或乙酰化的H3K14，并且富含rDNA反转录转座子R1和R2。数据显示，R1和R2反转录转座子在唾液腺中不活跃转录，可能导致侧翼rDNA基因的表观遗传沉默，这些序列的沉默机制可能部分独立于通过组蛋白H3在赖氨酸9处的甲基化和异染色质蛋白1的结合形成的异染色质。
Ribosomal DNA genes (rDNA) are found in tandem arrays of hundreds of repeated genes, but only a fraction of these genes are actively transcribed. The regulatory mechanism controlling the transition between active and inactive rDNA in higher eukaryotes is vital for cell survival. Here, we show that the nucleolus fromDrosophilasalivary gland cells contains two levels of chromatin organization reflecting differences in transcriptional activity: Decondensed chromatin is highly occupied with TATA-box-binding protein (TBP), phosphorylated H3S10, and acetylated H3K14, suggesting that rDNA in decondensed nucleolar areas is actively transcribed. Condensed chromatin lacks TBP, phosphorylated H3S10, or acetylated H3K14 and is enriched in the rDNA retrotransposons R1 and R2. The data show that R1 and R2 retrotransposons are not actively transcribed in salivary glands and may lead to the epigenetic silencing of flanking rDNA genes and that the silencing mechanisms of these sequences might be partially independent of heterochromatin formation by methylation of histone H3 at lysine 9 and binding of heterochromatin protein 1.