Département de Microbiologie et d'Infectiologie, Groupe ARN/RNA Group, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, 3001 12e Ave. Nord, Sherbrooke, Quebec J1H 5N4, Canada.
J Biol Chem. 2011 Aug 5;286(31):27132-8. doi: 10.1074/jbc.M111.220186. Epub 2011 Jun 15.
Telomeres containing vertebrate-type DNA repeats can be stably maintained in Saccharomyces cerevisiae cells. We show here that telomerase is required for growth of yeast cells containing these vertebrate-type telomeres. When present at the chromosome termini, these heterologous repeats elicit a DNA damage response and a certain deprotection of telomeres. The data also show that these phenotypes are due only to the terminal localization of the vertebrate repeats because if they are sandwiched between native yeast repeats, no phenotype is observed. Indeed and quite surprisingly, in this latter situation, telomeres are of virtually normal lengths, despite the presence of up to 50% of heterologous repeats. Furthermore, the presence of the distal vertebrate-type repeats can cause increased problems of the replication fork. These results show that in budding yeast the integrity of the 3' overhang is required for proper termination of telomere replication as well as protection.
端粒含有脊椎动物类型的 DNA 重复序列可以在酿酒酵母细胞中稳定维持。我们在这里表明，端粒酶是含有这些脊椎动物端粒的酵母细胞生长所必需的。当存在于染色体末端时，这些异源重复序列会引发 DNA 损伤反应，并导致端粒的一定去保护。这些数据还表明，这些表型仅归因于脊椎动物重复序列的末端定位，因为如果它们夹在天然酵母重复序列之间，则不会观察到表型。事实上，令人惊讶的是，在后一种情况下，尽管存在多达 50%的异源重复序列，但端粒的长度实际上是正常的。此外，远端脊椎动物类型重复序列的存在可能会导致复制叉的问题增加。这些结果表明，在芽殖酵母中，3'突出端的完整性是端粒复制以及保护的适当终止所必需的。
