The role of acetylation in rDNA transcription
The role of acetylation in rDNA transcription
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DOI：
10.1093/nar/29.20.4114
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发表时间：
2001-10-15
影响因子：
14.9
通讯作者：
Rothblum, LI
中科院分区：
文献类型：
--
作者：
Hirschler-Laszkiewicz, I;Cavanaugh, A;Rothblum, LI
用组蛋白脱乙酰酶(HDAC)抑制剂曲古抑素A(TSA)处理NIH3T3细胞后，rDNA报告基因和内源性rRNA基因转录水平呈剂量依赖性增加。使用抗乙酰化组蛋白H4抗体的染色质免疫沉淀显示了TSA对核糖体染色质的乙酰化状态的直接影响。TSA不能逆转视网膜母细胞瘤(Rb)蛋白对rDNA转录的抑制，提示Rb阻止rDNA转录的主要机制可能不涉及去乙酰酶对rDNA染色质的募集。组蛋白转乙酰酶p300、CBP和PCAF的过表达促进了NIH3T3细胞的转录。重组p300，而不是PCAF，在没有核小体的情况下，在体外刺激rDNA转录，提示TSA对rDNA转录的刺激可能具有染色质非依赖性成分。我们发现rDNA转录因子UBF在体内是乙酰化的。最后，我们还证明了CBP的核仁定位。我们的结果表明，高等真核生物核糖体染色质的组织并不是静态的，乙酰化可能直接通过组蛋白乙酰化和/或通过UBF或rDNA转录的其他成分之一的乙酰化来影响这些动态变化。
Treatment of NIH 3T3 cells with trichostatin A (TSA), an inhibitor of histone deacetylase (HDAC), resulted in a dose-dependent increase in transcription from a rDNA reporter and from endogenous rRNA genes. Chromatin immunoprecipitation using anti-acetyl-histone H4 antibodies demonstrated a direct effect of TSA on the acetylation state of the ribosomal chromatin. TSA did not reverse inhibition of transcription from the rDNA reporter by retinoblastoma (Rb) protein, suggesting that the main mechanism by which Rb blocks rDNA transcription may not involve recruitment of deacetylases to rDNA chromatin. Overexpression of histone transacetylases p300, CBP and PCAF stimulated transcription in transfected NIH 3T3 cells. Recombinant p300, but not PCAF, stimulated rDNA transcription in vitro in the absence of nucleosomes, suggesting that the stimulation of rDNA transcription by TSA might have a chromatin-independent component. We found that the rDNA transcription factor UBF was acetylated in vivo. Finally, we also demonstrated the nucleolar localization of CBP. Our results suggest that the organization of ribosomal chromatin of higher eukaryotes is not static and that acetylation may be involved in affecting these dynamic changes directly through histone acetylation and/or through acetylation of UBF or one of the other components of rDNA transcription.