Blasco María A
Molecular Oncology Program, Spanish National Cancer Centre (CNIO), E-28029 Madrid, Spain.
Carcinogenesis. 2004 Jul;25(7):1083-7. doi: 10.1093/carcin/bgh185. Epub 2004 May 6.
Telomeres are capping structures at the ends of eukaryotic chromosomes composed of TTAGGG repeats bound to an array of specialized proteins. Telomeres, together with centromeres, have been classically considered heterochromatic regions. Constitutive heterochromatin domains typically consist of repetitive DNA and have a very low gene content. In addition, constitutive heterochromatin is characterized by a number of hallmark histone modifications, as well as DNA modifications. In the case of pericentric heterochromatin, several activities responsible for these epigenetic modifications have been recently identified and characterized. In contrast, very little is still known on the architecture of telomeric chromatin, as well as on the activities that may regulate its structure and function. Here, we will discuss recent findings suggesting that telomeric chromatin shares many features with pericentric chromatin, and that disruption of telomeric heterochromatin results in changes in telomere length.
端粒是真核染色体末端的帽状结构，由与一系列特殊蛋白质结合的TTAGGG重复序列组成。端粒与着丝粒一起，传统上被认为是异染色质区域。组成型异染色质结构域通常由重复DNA组成，基因含量非常低。此外，组成型异染色质的特征是有许多标志性的组蛋白修饰以及DNA修饰。就着丝粒周围异染色质而言，最近已经鉴定并表征了几种负责这些表观遗传修饰的活性。相比之下，关于端粒染色质的结构以及可能调节其结构和功能的活性，我们仍然知之甚少。在这里，我们将讨论最近的研究结果，这些结果表明端粒染色质与着丝粒周围染色质有许多共同特征，并且端粒异染色质的破坏会导致端粒长度的变化。
