Alternative splicing of NURF301 generates distinct NURF chromatin remodeling complexes with altered modified histone binding specificities.
Alternative splicing of NURF301 generates distinct NURF chromatin remodeling complexes with altered modified histone binding specificities.
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DOI：
10.1371/journal.pgen.1000574
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发表时间：
2009-07
期刊：
影响因子：
4.5
通讯作者：
Badenhorst P
中科院分区：
文献类型：
--
作者：
Kwon SY;Xiao H;Wu C;Badenhorst P
果蝇NURF是一种含有iswi的染色质重塑复合体，可催化atp依赖性核小体滑动。通过滑动核小体，NURF可以改变染色质结构并调节转录。NURF301/BPTF是唯一的NURF特异性亚基，在招募复合体到靶基因中发挥重要作用。在这里，我们证明了三个NURF301异构体被表达，这些异构体编码功能不同的NURF染色质重塑复合物。全长NURF301包含一个c端溴域和并列的PHD指，分别结合Lys4位点三甲基化的组蛋白H3 （H3K4me3）和Lys16位点乙酰化的组蛋白H4 （H4K16Ac）。然而，也检测到缺乏这些c端结构域的NURF301异构体。这个截断的NURF301异构体组装了一个包含ISWI、NURF55和NURF38的复合体，表明存在第二类NURF重塑复合体，缺乏H3K4me3和H4K16Ac识别。通过比较无Nurf301突变体与去除c端PHD指和溴结构域的突变体的微阵列表达谱和表型，我们发现全长Nurf301对于大多数NURF基因靶点在幼虫中的正确表达不是必需的。然而，全长NURF301是精子发生所必需的。缺乏全长NURF的突变体表现为精细胞阻滞表型，不能表达精细胞分化基因的子集。我们的数据显示，识别翻译后组蛋白修饰的NURF atp依赖性染色质重塑复合体的变体是果蝇初级精母细胞分化的重要调节因子。核小体动力学的变化对转录、复制和修复等DNA交易具有深远的影响。染色质状态的改变可以通过组蛋白尾部的翻译后修饰或atp依赖性染色质重塑因子介导的能量依赖性核小体滑动来诱导。在这里，我们证明了果蝇染色质重塑因子NURF是由其大亚基NURF301的选择性剪接调节的。我们发现有三种NURF301同工异构体。其中一种缺乏c端蛋白结构域，该结构域识别翻译后组蛋白修饰H3K4me3和H4K16Ac，并可能允许NURF募集到修饰的组蛋白标记。利用全基因组表达谱，我们确定了需要这些结构域的NURF靶基因，从而识别了修饰的组蛋白标记。我们的研究结果表明，识别H3K4me3和H4K16Ac的NURF复合物对于大多数NURF基因靶点在幼虫中的正确表达不是必需的，但对于NURF在精子发生中的功能是必需的。我们发现NURF是果蝇精母细胞分化的重要调节因子。我们认为，选择性剪接提供了一种方便的机制来产生atp依赖性染色质重塑复合物的功能多样性，并允许产生具有改变染色质靶向特异性的重塑复合物。
Drosophila NURF is an ISWI–containing chromatin remodeling complex that catalyzes ATP–dependent nucleosome sliding. By sliding nucleosomes, NURF can alter chromatin structure and regulate transcription. NURF301/BPTF is the only NURF–specific subunit of NURF and is instrumental in recruiting the complex to target genes. Here we demonstrate that three NURF301 isoforms are expressed and that these encode functionally distinct NURF chromatin remodeling complexes. Full-length NURF301 contains a C-terminal bromodomain and juxtaposed PHD finger that bind histone H3 trimethylated at Lys4 (H3K4me3) and histone H4 acetylated at Lys16 (H4K16Ac) respectively. However, a NURF301 isoform that lacks these C-terminal domains is also detected. This truncated NURF301 isoform assembles a complex containing ISWI, NURF55, and NURF38, indicating that a second class of NURF remodeling complex, deficient in H3K4me3 and H4K16Ac recognition, exists. By comparing microarray expression profiles and phenotypes of null Nurf301 mutants with mutants that remove the C-terminal PHD fingers and bromodomain, we show that full-length NURF301 is not essential for correct expression of the majority of NURF gene targets in larvae. However, full-length NURF301 is required for spermatogenesis. Mutants that lack full-length NURF exhibit a spermatocyte arrest phenotype and fail to express a subset of spermatid differentiation genes. Our data reveal that variants of the NURF ATP–dependent chromatin remodeling complex that recognize post-translational histone modifications are important regulators of primary spermatocyte differentiation in Drosophila. Changes in nucleosome dynamics have a profound effect on DNA transactions such as transcription, replication, and repair. Altered chromatin states can be induced by post-translational modification of the histone tails or energy-dependent nucleosome sliding mediated by ATP–dependent chromatin remodeling factors. Here we demonstrate that the Drosophila chromatin remodeling factor NURF is regulated by alternative splicing of its large subunit NURF301. We show that three NURF301 isoforms occur. One of these lacks C-terminal protein domains that recognize the post-translational histone modifications H3K4me3 and H4K16Ac and that potentially allow recruitment of NURF to modified histone marks. Using whole genome expression profiling, we identify NURF target genes that require these domains and, hence, recognition of modified histone marks. Our results indicate that NURF complexes that recognize H3K4me3 and H4K16Ac are not essential for correct expression of the majority of NURF gene targets in larvae but are obligatory for NURF function in spermatogenesis. We show that NURF is an important regulator of spermatocyte differentiation in Drosophila. We suggest that alternative splicing provides a convenient mechanism to generate functional diversity of ATP–dependent chromatin remodeling complexes and allows the production of remodeling complexes with altered chromatin targeting specificities.
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影响因子：
10.5
作者：
Gdula, DA;Sandaltzopoulos, R;Wu, C
通讯作者：
Wu, C
影响因子：
16
作者：
Corona, DFV;Längst, G;Becker, PB
通讯作者：
Becker, PB
影响因子：
14.9
作者：
Delaunay, J;Mée, GL;Aït-Ahmed, O
通讯作者：
Aït-Ahmed, O
影响因子：
16
作者：
Deuring, R;Fanti, L;Tamkun, JW
通讯作者：
Tamkun, JW
DOI：
10.1111/j.2517-6161.1995.tb02031.x
发表时间：
1995-01-01
影响因子：
5.8
作者：
BENJAMINI, Y;HOCHBERG, Y
通讯作者：
HOCHBERG, Y