Fairhead Cécile, Dujon Bernard
Unité de Génétique Moléculaire des Levures, Département Structure et Dynamique des Génomes, Institut Pasteur, Paris, France.
FEMS Yeast Res. 2006 May;6(3):428-41. doi: 10.1111/j.1567-1364.2006.00033.x.
We have constructed a map of the duplicated regions of Kluyveromyces lactis subtelomeres. Seven out of 12 subtelomeres contain an almost identical 9 kb long segment starting from the end. This segment is bordered by a long terminal repeat element. Two of the subtelomeres share sequence similarity that extends over a total of 20 kb. The other subtelomeres also contain duplicated regions of 1-6 kb. Nonduplicated regions contain unique genes and genes from paralog families. All duplicated segments are in the same orientation with respect to the telomere, probably as a result of genetic exchange. We map the only two copies of retrotransposons in the genome, in subtelomeres. Low-complexity gene sequences that encode threonine- and serine-rich peptides are associated with the subtelomeres of K. lactis, as in Saccharomyces cerevisiae. The ubiquity of these sequences in hemiascomycete genomes, and the propensity they have to encode proteins with extracellular localization, make these genes ideal candidates for fast evolving 'contingency' genes involved in the adaptation of a species to its environment.
我们构建了乳酸克鲁维酵母亚端粒重复区域的图谱。12个亚端粒中有7个包含一个从末端开始的几乎相同的9 kb长片段。该片段由一个长末端重复元件界定。其中两个亚端粒共享延伸达20 kb的序列相似性。其他亚端粒也含有1 - 6 kb的重复区域。非重复区域包含独特基因和来自旁系同源家族的基因。所有重复片段相对于端粒具有相同的方向，这可能是基因交换的结果。我们在基因组中绘制了仅有的两个反转录转座子拷贝，它们位于亚端粒中。与酿酒酵母一样，编码富含苏氨酸和丝氨酸肽的低复杂性基因序列与乳酸克鲁维酵母的亚端粒相关。这些序列在半子囊菌基因组中的普遍性，以及它们编码具有细胞外定位蛋白质的倾向，使这些基因成为参与物种适应其环境快速进化的“应急”基因的理想候选者。
