Betts Lindroos Hanna, Ström Lena, Itoh Takehiko, Katou Yuki, Shirahige Katsuhiko, Sjögren Camilla
Department of Cell and Molecular Biology, Karolinska Institute, 171 77 Stockholm, Sweden.
Research Center for Advanced Science and Technology, Mitsubishi Research Institute, Inc., Tokyo 100-8141, Japan.
Mol Cell. 2006 Jun 23;22(6):755-767. doi: 10.1016/j.molcel.2006.05.014.
The SMC protein complexes safeguard genomic integrity through their functions in chromosome segregation and repair. The chromosomal localization of the budding yeast Smc5/6 complex determined here reveals that the complex works specifically on the duplicated genome in differently regulated pathways. The first controls the association to centromeres and chromosome arms in unchallenged cells, the second regulates the association to DNA breaks, and the third directs the complex to the chromosome arm that harbors the ribosomal DNA arrays. The chromosomal interaction pattern predicts a function that becomes more important with increasing chromosome length and that the complex's role in unchallenged cells is independent of DNA damage. Additionally, localization of Smc6 to collapsed replication forks indicates an involvement in their rescue. Altogether this shows that the complex maintains genomic integrity in multiple ways, and evidence is presented that the Smc5/6 complex is needed during replication to prevent the accumulation of branched chromosome structures.
SMC蛋白复合物通过其在染色体分离和修复中的功能来维护基因组完整性。此处确定的出芽酵母Smc5/6复合物的染色体定位表明，该复合物在不同调控途径中专门作用于复制后的基因组。第一种途径控制在未受挑战的细胞中与着丝粒和染色体臂的结合，第二种途径调节与DNA断裂处的结合，第三种途径将该复合物导向含有核糖体DNA阵列的染色体臂。染色体相互作用模式预示着一种随着染色体长度增加而变得更为重要的功能，并且该复合物在未受挑战的细胞中的作用与DNA损伤无关。此外，Smc6定位于坍塌的复制叉表明其参与了复制叉的挽救。总之，这表明该复合物以多种方式维持基因组完整性，并且有证据表明在复制过程中需要Smc5/6复合物来防止分支染色体结构的积累。
