Sacerdot Christine, Casaregola Serge, Lafontaine Ingrid, Tekaia Fredj, Dujon Bernard, Ozier-Kalogeropoulos Odile
Institut Pasteur, Unité de Génétique Moléculaire des Levures, CNRS, URA 2171, Université Pierre et Marie Curie-Paris 06, Paris, France.
FEMS Yeast Res. 2008 Sep;8(6):846-57. doi: 10.1111/j.1567-1364.2008.00409.x. Epub 2008 Jul 30.
Abstract Transfer of fragments of mtDNA to the nuclear genome is a general phenomenon that gives rise to NUMTs (NUclear sequences of MiTochondrial origin). We present here the first comparative analysis of the NUMT content of entirely sequenced species belonging to a monophyletic group, the hemiascomycetous yeasts (Candida glabrata, Kluyveromyces lactis, Kluyveromyces thermotolerans, Debaryomyces hansenii and Yarrowia lipolytica, along with the updated NUMT content of Saccharomyces cerevisiae). This study revealed a huge diversity in NUMT number and organization across the six species. Debaryomyces hansenii harbors the highest number of NUMTs (145), half of which are distributed in numerous large mosaics of up to eight NUMTs arising from multiple noncontiguous mtDNA fragments inserted at the same chromosomal locus. Most NUMTs, in all species, are found within intergenic regions including seven NUMTs in pseudogenes. However, five NUMTs overlap a gene, suggesting a positive impact of NUMTs on protein evolution. Contrary to the other species, K. lactis and K. thermotolerans harbor only a few diverged NUMTs, suggesting that mitochondrial transfer to the nuclear genome has decreased or ceased in these phylogenetic branches. The dynamics of NUMT acquisition and loss are illustrated here by their species-specific distribution.
摘要 线粒体DNA片段向核基因组的转移是一种普遍现象，会产生线粒体起源的核序列（NUMTs）。我们在此展示了对属于单系群的全序列物种（半子囊菌酵母，包括光滑念珠菌、乳酸克鲁维酵母、耐热克鲁维酵母、汉逊德巴利酵母和解脂耶氏酵母，以及酿酒酵母更新后的NUMT含量）的NUMT含量进行的首次比较分析。这项研究揭示了这六个物种在NUMT数量和组织方面的巨大差异。汉逊德巴利酵母拥有最多的NUMT（145个），其中一半分布在由插入同一染色体位点的多个不连续线粒体DNA片段产生的多达八个NUMT的众多大镶嵌体中。在所有物种中，大多数NUMT位于基因间区域，包括假基因中的七个NUMT。然而，有五个NUMT与一个基因重叠，表明NUMT对蛋白质进化有积极影响。与其他物种相反，乳酸克鲁维酵母和耐热克鲁维酵母仅含有少数分化的NUMT，这表明在这些系统发育分支中，线粒体向核基因组的转移已经减少或停止。NUMT获得和丢失的动态过程在此通过它们物种特异性的分布得以体现。
