Department of Biology, Emory University, Atlanta, GA, USA.
PLoS One. 2013;8(1):e53091. doi: 10.1371/journal.pone.0053091. Epub 2013 Jan 16.
Strains from a collection of Drosophila GFP protein trap lines express GFP in the normal tissues where the endogenous protein is present. This collection can be used to screen for proteins distributed in the nucleus in a non-uniform pattern.
METHODOLOGY/PRINCIPAL FINDINGS: We analyzed four lines that show peripheral or punctate nuclear staining. One of these lines affects an uncharacterized gene named CG11138. The CG11138 protein shows a punctate distribution in the nuclear periphery similar to that of Drosophila insulator proteins but does not co-localize with known insulators. Interestingly, mutations in Lamin proteins result in alterations in CG11138 localization, suggesting that this protein may be a novel component of the nuclear lamina. A second line affects the Decondensation factor 31 (Df31) gene, which encodes a protein with a unique nuclear distribution that appears to segment the nucleus into four different compartments. The X-chromosome of males is confined to one of these compartments. We also find that Drosophila Nucleoplasmin (dNlp) is present in regions of active transcription. Heat shock leads to loss of dNlp from previously transcribed regions of polytene chromosome without redistribution to the heat shock genes. Analysis of Stonewall (Stwl), a protein previously found to be necessary for the maintenance of germline stem cells, shows that Stwl is present in a punctate pattern in the nucleus that partially overlaps with that of known insulator proteins. Finally we show that Stwl, dNlp, and Df31 form part of a highly interactive network. The properties of other components of this network may help understand the role of these proteins in nuclear biology.
CONCLUSIONS/SIGNIFICANCE: These results establish screening of GFP protein trap alleles as a strategy to identify factors with novel cellular functions. Information gained from the analysis of CG11138 Stwl, dNlp, and Df31 sets the stage for future studies of these proteins.
从一组 Drosophila GFP 蛋白捕获系中分离出的菌株在存在内源性蛋白的正常组织中表达 GFP。该集合可用于筛选非均匀分布于核内的蛋白质。
方法/主要发现：我们分析了四个显示周边或点状核染色的品系。其中一个影响一个未被描述的名为 CG11138 的基因。CG11138 蛋白在核周呈点状分布，类似于果蝇绝缘子蛋白，但不与已知的绝缘子共定位。有趣的是，Lamin 蛋白的突变导致 CG11138 定位的改变，表明该蛋白可能是核纤层的一个新成分。第二条线影响去凝聚因子 31（Df31）基因，该基因编码一种具有独特核分布的蛋白质，似乎将核分割成四个不同的隔室。雄性的 X 染色体局限于其中一个隔室。我们还发现果蝇核质蛋白（dNlp）存在于活跃转录的区域。热激导致 dNlp 从多线染色体以前转录的区域丢失，而不会重新分配到热激基因。分析先前发现对生殖干细胞维持必需的 Stonewall（Stwl）蛋白，表明 Stwl 以点状模式存在于核中，部分与已知的绝缘子蛋白重叠。最后，我们表明 Stwl、dNlp 和 Df31 构成了一个高度相互作用的网络的一部分。该网络的其他成分的特性可能有助于理解这些蛋白质在核生物学中的作用。
结论/意义：这些结果确立了 GFP 蛋白捕获等位基因的筛选作为鉴定具有新细胞功能的因素的策略。从 CG11138、Stwl、dNlp 和 Df31 的分析中获得的信息为这些蛋白质的进一步研究奠定了基础。
