Pindyurin Alexey V, Moorman Celine, de Wit Elzo, Belyakin Stepan N, Belyaeva Elena S, Christophides George K, Kafatos Fotis C, van Steensel Bas, Zhimulev Igor F
Institute of Cytology and Genetics of Siberian Division, Russian Academy of Sciences, Novosibirsk 630090, Russia.
J Cell Sci. 2007 Jul 15;120(Pt 14):2344-51. doi: 10.1242/jcs.006007.
Drosophila melanogaster Suppressor of Under-Replication (SuUR) gene encodes a protein that modulates replicative properties of heterochromatin in endocycles of polytene cells. The SuUR mutation abolishes underreplication of intercalary heterochromatin and results in partial underreplication of pericentric heterochromatin. We performed a genome-wide mapping of SUUR target genes in non-polytenic Drosophila Kc cells by using the DamID approach. We show that SUUR preferentially binds genes that are transcriptionally silent and late-replicated. Distinct subsets of SUUR targets are associated with PcG proteins (Pc and Esc; Polycomb and Extra sexcombs), heterochromatic proteins [HP1 and SU(VAR)3-9] and B-type lamin. The SUUR binding profile negatively correlates with the DNA polytenization levels of salivary gland polytene chromosomes. Finally, SUUR target genes are repressed in Drosophila embryos and gradually activated later in development. Together these results suggest that SUUR is a ubiquitous marker of heterochromatin in different cell types.
果蝇黑腹果蝇复制不足抑制因子（SuUR）基因编码一种蛋白质，该蛋白质可调节多线细胞内循环中异染色质的复制特性。SuUR突变消除了居间异染色质的复制不足，并导致着丝粒周围异染色质的部分复制不足。我们通过使用DamID方法在非多线果蝇Kc细胞中对SUUR靶基因进行了全基因组定位。我们发现SUUR优先结合转录沉默和复制较晚的基因。SUUR靶标的不同子集与PcG蛋白（Pc和Esc；多梳蛋白和超性梳蛋白）、异染色质蛋白[HP1和SU(VAR)3-9]和B型核纤层蛋白相关。SUUR结合图谱与唾液腺多线染色体的DNA多线化水平呈负相关。最后，SUUR靶基因在果蝇胚胎中受到抑制，并在发育后期逐渐被激活。这些结果共同表明，SUUR是不同细胞类型中异染色质的普遍标志物。
