Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, China.
Acta Biochim Biophys Sin (Shanghai). 2010 Dec;42(12):839-46. doi: 10.1093/abbs/gmq095. Epub 2010 Oct 26.
Cenp-F (also named mitosin) is a 350-kDa human kinetochore protein important for the mitotic progression. It is also a nuclear matrix protein in interphase cells. Here, we showed that overexpression of N-terminal deletion mutants of Cenp-F containing the C-terminal 112 residues induced chromatin condensation into numerous aggregates of varying sizes in interphase nucleus, colocalizing with the exogenous proteins. In situ hybridization using whole chromosome painting probes indicated that the chromatin aggregates were not prematurely condensed individual chromosomes. Neither were they due to apoptosis. We provided evidence showing association of Cenp-F with certain regions of interphase chromatin fibers. Cenp-F associated with the DNA-dependent protein kinase (DNA-PK), a trimeric protein complex critical for genome homeostasis. Moreover, the DNA-PK association activity of Cenp-F mutants correlated with their ability to induce chromatin aggregation. These results imply a role of Cenp-F in organization of interphase chromatin through association and possibly regulation of DNA-PK.
着丝粒蛋白 F（也称为 mitosin）是一种 350kDa 的人着丝粒蛋白，对于有丝分裂进程很重要。它也是间期细胞的核基质蛋白。在这里，我们发现表达含有 C 端 112 个残基的 N 端缺失突变体的 Cenp-F 会诱导间期核中的染色质凝聚成大小不等的多个聚集体，并与外源性蛋白质共定位。使用整条染色体涂染探针的原位杂交表明，染色质聚集体不是过早凝聚的单个染色体。它们也不是细胞凋亡的结果。我们提供的证据表明 Cenp-F 与间期染色质纤维的某些区域相关联。 Cenp-F 与 DNA 依赖性蛋白激酶（DNA-PK）相关联，该蛋白复合物是基因组稳态的关键三聚体蛋白复合物。此外， Cenp-F 突变体与 DNA-PK 的关联活性与其诱导染色质聚集的能力相关。这些结果表明 Cenp-F 通过与 DNA-PK 的关联和可能的调节作用在间期染色质的组织中发挥作用。
