Thierry Agnès, Bouchier Christiane, Dujon Bernard, Richard Guy-Franck
Institut Pasteur, Unité de Génétique Moléculaire des Levures, CNRS, URA2171, F-75015 Paris, France.
Nucleic Acids Res. 2008 Oct;36(18):5970-82. doi: 10.1093/nar/gkn594. Epub 2008 Sep 23.
Minisatellites are DNA tandem repeats that are found in all sequenced genomes. In the yeast Saccharomyces cerevisiae, they are frequently encountered in genes encoding cell wall proteins. Minisatellites present in the completely sequenced genome of the pathogenic yeast Candida glabrata were similarly analyzed, and two new types of minisatellites were discovered: minisatellites that are composed of two different intermingled repeats (called compound minisatellites), and minisatellites containing unusually long repeated motifs (126-429 bp). These long repeat minisatellites may reach unusual length for such elements (up to 10 kb). Due to these peculiar properties, they have been named 'megasatellites'. They are found essentially in genes involved in cell-cell adhesion, and could therefore be involved in the ability of this opportunistic pathogen to colonize the human host. In addition to megasatellites, found in large paralogous gene families, there are 93 minisatellites with simple shorter motifs, comparable to those found in S. cerevisiae. Most of the time, these minisatellites are not conserved between C. glabrata and S. cerevisiae, although their host genes are well conserved, raising the question of an active mechanism creating minisatellites de novo in hemiascomycetes.
微卫星是在所有已测序基因组中都能找到的DNA串联重复序列。在酿酒酵母中，它们经常出现在编码细胞壁蛋白的基因中。对致病性酵母光滑念珠菌的全基因组测序中存在的微卫星进行了类似分析，发现了两种新型微卫星：由两种不同的混合重复序列组成的微卫星（称为复合微卫星），以及包含异常长重复基序（126 - 429 bp）的微卫星。这些长重复微卫星对于此类元件而言可能达到异常长度（长达10 kb）。由于这些特殊性质，它们被命名为“巨卫星”。它们主要存在于参与细胞间黏附的基因中，因此可能与这种机会性病原体在人类宿主中定殖的能力有关。除了在大型旁系同源基因家族中发现的巨卫星外，还有93个具有简单较短基序的微卫星，与酿酒酵母中发现的微卫星类似。大多数情况下，尽管它们的宿主基因高度保守，但这些微卫星在光滑念珠菌和酿酒酵母之间并不保守，这就提出了半子囊菌中从头产生微卫星的一种活跃机制的问题。
