McEachern M J, Blackburn E H
Department of Microbiology and Immunology, University of California, San Francisco 94143.
Proc Natl Acad Sci U S A. 1994 Apr 12;91(8):3453-7. doi: 10.1073/pnas.91.8.3453.
Telomeric DNA sequences have generally been found to be remarkably conserved in evolution, typically consisting of repeated, very short sequence units containing clusters of G residues. Recently however the telomeric DNA of the asexual yeast Candida albicans was shown to consist of much longer repeat units. Here we report the identification of seven additional telomeric sequences from sexual and asexual budding yeast species. The telomeric repeat units from this group of relatively closely related species show more phylogenetic diversity in length (8-25 bp), sequence, and composition than has been seen previously throughout a wide phylogenetic range of other eukaryotes. We also show that certain strains of the asexual diploid species Candida tropicalis have two forms of telomeric repeats, which appear to differ by a single base pair. Despite their great diversity, the telomeric repeat units of C. albicans, Saccharomyces cerevisiae, and all of the species we have examined in this report share a conserved approximately 6-bp motif of T and G residues resembling more typical telomeric sequences.
一般而言，端粒DNA序列在进化过程中高度保守，通常由重复的、非常短的序列单元组成，这些单元包含G残基簇。然而，最近有研究表明，无性酵母白色念珠菌的端粒DNA由长得多的重复单元组成。在此，我们报告了从有性和无性出芽酵母物种中鉴定出的另外七种端粒序列。与之前在广泛的其他真核生物系统发育范围内所观察到的相比，这一组亲缘关系相对较近的物种的端粒重复单元在长度（8 - 25个碱基对）、序列和组成上表现出更多的系统发育多样性。我们还表明，无性二倍体物种热带念珠菌的某些菌株具有两种形式的端粒重复序列，它们似乎仅相差一个碱基对。尽管它们具有很大的多样性，但白色念珠菌、酿酒酵母以及我们在本报告中研究的所有物种的端粒重复单元都共享一个保守的、大约6个碱基对的T和G残基基序，类似于更典型的端粒序列。
Zotero 插件
