Institute of Genetics and Biophysics 'A. Buzzati-Traverso', CNR, 80131 Naples, Italy.
Genes (Basel). 2020 May 28;11(6):595. doi: 10.3390/genes11060595.
Pericentric heterochromatin (PCH) is a particular form of constitutive heterochromatin that is localized to both sides of centromeres and that forms silent compartments enriched in repressive marks. These genomic regions contain species-specific repetitive satellite DNA that differs in terms of nucleotide sequences and repeat lengths. In spite of this sequence diversity, PCH is involved in many biological phenomena that are conserved among species, including centromere function, the preservation of genome integrity, the suppression of spurious recombination during meiosis, and the organization of genomic silent compartments in the nucleus. PCH organization and maintenance of its repressive state is tightly regulated by a plethora of factors, including enzymes (e.g., DNA methyltransferases, histone deacetylases, and histone methyltransferases), DNA and histone methylation binding factors (e.g., MECP2 and HP1), chromatin remodeling proteins (e.g., ATRX and DAXX), and non-coding RNAs. This evidence helps us to understand how PCH organization is crucial for genome integrity. It then follows that alterations to the molecular signature of PCH might contribute to the onset of many genetic pathologies and to cancer progression. Here, we describe the most recent updates on the molecular mechanisms known to underlie PCH organization and function.
着丝粒异染色质（PCH）是一种特殊形式的组成型异染色质，定位于着丝粒的两侧，形成富含抑制性标记的沉默区。这些基因组区域包含具有物种特异性的重复卫星 DNA，其在核苷酸序列和重复长度方面存在差异。尽管存在这种序列多样性，但 PCH 参与了许多在物种间保守的生物学现象，包括着丝粒功能、基因组完整性的维持、减数分裂中假重组的抑制以及核内基因组沉默区的组织。PCH 的组织和抑制状态的维持受到多种因素的严格调控，包括酶（例如，DNA 甲基转移酶、组蛋白去乙酰化酶和组蛋白甲基转移酶）、DNA 和组蛋白甲基化结合因子（例如，MECP2 和 HP1）、染色质重塑蛋白（例如，ATRX 和 DAXX）和非编码 RNA。这些证据有助于我们了解 PCH 组织对于基因组完整性的重要性。因此，可以推断 PCH 分子特征的改变可能导致许多遗传病理学和癌症的发生。在这里，我们描述了目前已知的 PCH 组织和功能的分子机制的最新进展。
