Craven R J, Petes T D
Department of Biology, Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, North Carolina 27599-3280, USA.
Genetics. 1999 Aug;152(4):1531-41. doi: 10.1093/genetics/152.4.1531.
In the yeast Saccharomyces cerevisiae, chromosomes terminate with approximately 400 bp of a simple repeat poly(TG(1-3)). Based on the arrangement of subtelomeric X and Y' repeats, two types of yeast telomeres exist, those with both X and Y' (Y' telomeres) and those with only X (X telomeres). Mutations that result in abnormally short or abnormally long poly(TG(1-3)) tracts have been previously identified. In this study, we investigated telomere length in strains with two classes of mutations, one that resulted in short poly(TG(1-3)) tracts (tel1) and one that resulted in elongated tracts (pif1, rap1-17, rif1, or rif2). In the tel1 pif1 strain, Y' telomeres had about the same length as those in tel1 strains and X telomeres had lengths intermediate between those in tel1 and pif1 strains. Strains with either the tel1 rap1-17 or tel1 rif2 genotypes had short tracts for all chromosome ends examined, demonstrating that the telomere elongation characteristic of rap1-17 and rif2 strains is Tel1p-dependent. In strains of the tel1 rif1 or tel1 rif1 rif2 genotypes, telomeres with Y' repeats had short terminal tracts, whereas most of the X telomeres had long terminal tracts. These results demonstrate that the regulation of telomere length is different for X and Y' telomeres.
在酿酒酵母中，染色体末端是约400 bp的简单重复序列poly(TG(1-3))。根据亚端粒X和Y'重复序列的排列，存在两种类型的酵母端粒，即同时具有X和Y'的端粒（Y'端粒）和仅具有X的端粒（X端粒）。先前已经鉴定出导致poly(TG(1-3))序列异常短或异常长的突变。在本研究中，我们调查了两类突变菌株中的端粒长度，一类导致poly(TG(1-3))序列短（tel1），另一类导致序列延长（pif1、rap1-17、rif1或rif2）。在tel1 pif1菌株中，Y'端粒的长度与tel1菌株中的大致相同，而X端粒的长度介于tel1和pif1菌株之间。tel1 rap1-17或tel1 rif2基因型的菌株，在所检测的所有染色体末端都有短序列，这表明rap1-17和rif2菌株的端粒延长特征依赖于Tel1p。在tel1 rif1或tel1 rif1 rif2基因型的菌株中，具有Y'重复序列的端粒有短的末端序列，而大多数X端粒有长的末端序列。这些结果表明，X和Y'端粒的端粒长度调节是不同的。
