Marzullo Marta, Gatti Maurizio
a Department of Biology and Biotechnology ; University of Rome ; Sapienza , Italy.
b IBPM CNR, University of Rome ; Rome , Italy.
Fly (Austin). 2015;9(3):121-5. doi: 10.1080/19336934.2015.1131882.
Drosophila telomeres are maintained by transposition to chromosome ends of the HeT-A, TART and TAHRE retrotransposons, collectively designated as HTT. Although all Drosophila telomeres terminate with HTT arrays and are capped by the terminin complex, they differ in the type of subtelomeric chromatin. The HTT sequences of YS, YL, XR, and 4L are juxtaposed to constitutive heterochromatin, while the HTTs of the other telomeres are linked to either the TAS repeat-associated chromatin (XL, 2L, 2R, 3L, 3R) or to the specialized 4R chromatin. We found that mutations in pendolino (peo) cause (telomeric fusions) that preferentially involve the heterochromatin-associated telomeres (Ha-telomeres), a telomeric fusion pattern never observed in the other 10 telomere-capping mutants characterized so far. Peo, is homologous to the E2 variant ubiquitin-conjugating enzymes and is required for DNA replication. Our analyses lead us to hypothesize that DNA replication in Peo-depleted cells results in specific fusigenic lesions concentrated in Ha-telomeres. These data provide the first demonstration that subtelomeres can affect telomere fusion.
果蝇端粒通过HeT-A、TART和TAHRE逆转录转座子（统称为HTT）转座至染色体末端来维持。尽管所有果蝇端粒都以HTT阵列终止并由端粒蛋白复合体加帽，但它们在亚端粒染色质类型上存在差异。YS、YL、XR和4L的HTT序列与组成型异染色质并列，而其他端粒的HTT则与TAS重复相关染色质（XL、2L、2R、3L、3R）或特殊的4R染色质相连。我们发现，pendolino（peo）基因的突变会导致（端粒融合），这种融合优先涉及与异染色质相关的端粒（Ha-端粒），这是一种在目前已鉴定的其他10种端粒加帽突变体中从未观察到的端粒融合模式。Peo与E2变体泛素结合酶同源，是DNA复制所必需的。我们的分析使我们推测，Peo缺失细胞中的DNA复制会导致集中在Ha-端粒的特定致融合损伤。这些数据首次证明亚端粒可以影响端粒融合。
