The distribution of polycomb-group proteins during cell division and development in Drosophila embryos: impact on models for silencing.
The distribution of polycomb-group proteins during cell division and development in Drosophila embryos: impact on models for silencing.
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DOI：
10.1083/jcb.141.2.469
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发表时间：
1998-04-20
影响因子：
7.8
通讯作者：
Arndt-Jovin, DJ
中科院分区：
文献类型：
--
作者：
Buchenau, P;Hodgson, J;Strutt, H;Arndt-Jovin, DJ
通过多色共聚焦荧光显微镜分析了固定的整装果蝇胚胎中三种多梳组（PcG）蛋白——多梳蛋白、多同源异形蛋白和后性梳蛋白的亚细胞三维分布。这三种蛋白在大多数间期核体积内以100个或更多位点的复杂模式定位。绝大多数位点中蛋白强度的分布相当狭窄，这与PcG通过聚集到亚核区域介导对受抑制靶基因的隔离这一观点相悖。与位置效应花斑（PEV）抑制的情况（Csink, A.K., 和S. Henikoff. 1996.《自然》381:529–531）相反，PcG蛋白的出现与高浓度DNA之间缺乏相关性，这表明沉默基因并非靶向核内的异染色质区域。核内转录位点和PcG结合位点之间有明显区别，这支持了大多数PcG结合位点是抑制复合物位点这一假设。尽管PcG蛋白能维持组织特异性抑制长达14个细胞世代，但此处所研究的蛋白在有丝分裂期间明显从染色质上解离，并以不同方式分散到细胞质中。对整装胚胎中荧光强度的定量分析表明，解离的蛋白存在于细胞质中。我们确定少于2%的多同源异形蛋白（PH）仍附着在后期和末期染色体上。所研究的三种蛋白在前期解离以及在末期重新结合的速率和程度各不相同。这些观察结果对PcG介导的基因抑制机制和维持模型具有重要意义。
The subcellular three-dimensional distribution of three polycomb-group (PcG) proteins—polycomb, polyhomeotic and posterior sex combs—in fixed whole-mount Drosophila embryos was analyzed by multicolor confocal fluorescence microscopy. All three proteins are localized in complex patterns of 100 or more loci throughout most of the interphase nuclear volume. The rather narrow distribution of the protein intensities in the vast majority of loci argues against a PcG-mediated sequestration of repressed target genes by aggregation into subnuclear domains. In contrast to the case for PEV repression (Csink, A.K., and S. Henikoff. 1996. Nature. 381:529–531), there is a lack of correlation between the occurrence of PcG proteins and high concentrations of DNA, demonstrating that the silenced genes are not targeted to heterochromatic regions within the nucleus. There is a clear distinction between sites of transcription in the nucleus and sites of PcG binding, supporting the assumption that most PcG binding loci are sites of repressive complexes. Although the PcG proteins maintain tissue-specific repression for up to 14 cell generations, the proteins studied here visibly dissociate from the chromatin during mitosis, and disperse into the cytoplasm in a differential manner. Quantitation of the fluorescence intensities in the whole mount embryos demonstrate that the dissociated proteins are present in the cytoplasm. We determined that <2% of PH remains attached to late metaphase and anaphase chromosomes. Each of the three proteins that were studied has a different rate and extent of dissociation at prophase and reassociation at telophase. These observations have important implications for models of the mechanism and maintenance of PcG- mediated gene repression.
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影响因子：
1.6
作者：
BELMONT, AS;BRAUNFELD, MB;AGARD, DA
通讯作者：
AGARD, DA
影响因子：
11.4
作者：
CHINWALLA, V;JANE, EP;HARTE, PJ
通讯作者：
HARTE, PJ
影响因子：
64.5
作者：
Dernburg, AF;Broman, KW;Sedat, JW
通讯作者：
Sedat, JW
DOI：
10.1007/bf00288601
发表时间：
1995-02-06
期刊：
MOLECULAR & GENERAL GENETICS
影响因子：
--
作者：
CAMPBELL, RB;SINCLAIR, DAR;BROCK, HW
通讯作者：
BROCK, HW
影响因子：
2
作者：
Demandolx, D;Davoust, J
通讯作者：
Davoust, J