SUV39h-independent association of HP1β with fibrillarin-positive nucleolar regions
SUV39h-independent association of HP1β with fibrillarin-positive nucleolar regions
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DOI：
10.1007/s00412-009-0252-2
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发表时间：
2010-06-01
期刊：
影响因子：
1.6
通讯作者：
Kozubek, Stanislav
中科院分区：
文献类型：
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作者：
Horakova, Andrea Harnicarova;Bartova, Eva;Kozubek, Stanislav
异染色质蛋白1 （HP1）与组蛋白H3赖氨酸9 （H3K9）甲基化位点结合，主要负责基因沉默和异染色质的形成。我们观察到HP1 β位于染色质中心和纤维蛋白阳性核仁内部。然而，HP1 α和HP1 γ在较小程度上占据纤维蛋白阳性区室，这与rDNA基因启动子处HP1亚型的不同水平相对应。组蛋白甲基转移酶SUV39h的缺乏和/或组蛋白去乙酰化酶（HDACi）的抑制会降低HP1 β和H3K9在色中心的三甲基化，但不会降低与RNA聚合酶i共定位的纤原蛋白阳性区域的三甲基化。同样，SUV39h和HDACi依赖的核仁重排和rDNA转录的抑制不会影响HP1 β和纤原蛋白之间的关联。此外，HP1 β在核仁中的存在可能与核糖体基因的转录以及纤原蛋白在核仁过程中的作用有关。
Heterochromatin protein 1 (HP1), which binds to sites of histone H3 lysine 9 (H3K9) methylation, is primarily responsible for gene silencing and the formation of heterochromatin. We observed that HP1 beta is located in both the chromocenters and fibrillarin-positive nucleoli interiors. However, HP1 alpha and HP1 gamma occupied fibrillarin-positive compartments to a lesser extent, corresponding to the distinct levels of HP1 subtypes at the promoter of rDNA genes. Deficiency of histone methyltransferases SUV39h and/or inhibition of histone deacetylases (HDACi) decreased HP1 beta and H3K9 trimethylation at chromocenters, but not in fibrillarin-positive regions that co-localized with RNA polymerase I. Similarly, SUV39h- and HDACi-dependent nucleolar rearrangement and inhibition of rDNA transcription did not affect the association between HP1 beta and fibrillarin. Moreover, the presence of HP1 beta in nucleoli is likely connected with transcription of ribosomal genes and with the role of fibrillarin in nucleolar processes.