Arabidopsis histone deacetylase HDA6 is required for maintenance of transcriptional gene silencing and determines nuclear organization of rDNA repeats
Arabidopsis histone deacetylase HDA6 is required for maintenance of transcriptional gene silencing and determines nuclear organization of rDNA repeats
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DOI：
10.1105/tpc.018754
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发表时间：
2004-04-01
期刊：
影响因子：
11.6
通讯作者：
Scheid, OM
中科院分区：
文献类型：
--
作者：
Probst, AV;Fagard, M;Scheid, OM
在许多真核生物中，组蛋白乙酰化和去乙酰化与转录激活和沉默有关。完成这些修饰的酶的基因家族在序列和表达水平上显示出惊人的多样性，表明对不同的靶标具有高度的特异性。我们发现，拟南芥HDA6基因的突变导致了几个重复的转基因和内源模板转录沉默的丧失。令人惊讶的是，组蛋白H4乙酰化的总水平仅受到轻微影响，而显著的超乙酰化仅限于包含rDNA重复的核仁组织者区域。这种转变与组蛋白3在Lys残基4上甲基化增加、DNA甲基化模式改变以及伴随的染色质解缩相一致。这些结果表明，HDA6可能在调节rRNA基因的活性方面发挥作用，这种控制可能在功能上与沉默其他重复模板以及它先前在RNA指导的DNA甲基化中所扮演的角色有关。
Histone acetylation and deacetylation are connected with transcriptional activation and silencing in many eukaryotic organisms. Gene families for enzymes that accomplish these modifications show a surprising multiplicity in sequence and expression levels, suggesting a high specificity for different targets. We show that mutations in Arabidopsis (Arabidopsis thaliana) HDA6, a putative class I histone deacetylase gene, result in loss of transcriptional silencing from several repetitive transgenic and endogenous templates. Surprisingly, total levels of histone H4 acetylation are only slightly affected, whereas significant hyperacetylation is restricted to the nucleolus organizer regions that contain the rDNA repeats. This switch coincides with an increase of histone 3 methylation at Lys residue 4, a modified DNA methylation pattern, and a concomitant decondensation of the chromatin. These results indicate that HDA6 might play a role in regulating activity of rRNA genes, and this control might be functionally linked to silencing of other repetitive templates and to its previously assigned role in RNA-directed DNA methylation.