Department of Biology, Southeast Missouri State University, Cape Girardeau, Missouri 63701.
Pasteur Institute, Cenci-Bolognetti Foundation and Department of Biology and Biotechnology, University of Rome "La Sapienza," 00185, Italy.
Genetics. 2017 Nov;207(3):949-959. doi: 10.1534/genetics.117.300317. Epub 2017 Sep 23.
The addition of a new telomere onto a chromosome break, a process termed healing, has been studied extensively in organisms that utilize telomerase to maintain their telomeres. In comparison, relatively little is known about how new telomeres are constructed on broken chromosomes in organisms that do not use telomerase. Chromosome healing was studied in somatic and germline cells of , a nontelomerase species. We observed, for the first time, that broken chromosomes can be healed in somatic cells. In addition, overexpression of the telomere cap component Hiphop increased the survival of somatic cells with broken chromosomes, while the cap component HP1 did not, and overexpression of the cap protein HOAP decreased their survival. In the male germline, Hiphop overexpression greatly increased the transmission of healed chromosomes. These results indicate that Hiphop can stimulate healing of a chromosome break. We suggest that this reflects a unique function of Hiphop: it is capable of seeding formation of a new telomeric cap on a chromosome end that lacks a telomere.
在利用端粒酶维持端粒的生物体中，人们对染色体断裂处添加新端粒的过程（称为愈合）进行了广泛研究。相比之下，对于不使用端粒酶的生物体中，断裂染色体上如何构建新端粒的了解相对较少。本研究在非端粒酶物种 的体细胞和生殖细胞中研究了染色体愈合。我们首次观察到，体细胞中的断裂染色体可以愈合。此外，端粒帽成分 Hiphop 的过表达增加了带有断裂染色体的体细胞的存活率，而帽成分 HP1 则没有，端粒帽蛋白 HOAP 的过表达降低了它们的存活率。在雄性生殖细胞中，Hiphop 的过表达大大增加了愈合染色体的传递。这些结果表明，Hiphop 可以刺激染色体断裂的愈合。我们认为这反映了 Hiphop 的一个独特功能：它能够在缺乏端粒的染色体末端形成新的端粒帽。
