Hanekamp T, Thorsness P E
Department of Molecular Biology, University of Wyoming, Laramie, Wyoming 82071-3944, USA.
Curr Genet. 1999 Jan;34(6):438-48. doi: 10.1007/s002940050418.
Mutation of YME genes in yeast results in a high rate of mitochondrial DNA escape to the nucleus. The synthetic respiratory growth defect of yme1 yme2 yeast strains is suppressed by recessive mutations in YNT20. Inactivation of YNT20 creates a cold-sensitive respiratory growth defect that is more pronounced in a yme1 background and which is suppressed by yme2. Inactivation of YNT20 causes a qualitative reduction in the rate of mitochondrial DNA escape in yme1, but not yme2, strains, suggesting that YNT20 plays a role in the yme1-mediated mitochondrial DNA escape pathway. YNT20p is a soluble mitochondrial protein that belongs to a subfamily of putative 3'-5' exonucleases. Furthermore, conserved sequence elements in Yme2p suggest that this protein may also function as an exonuclease.
酵母中YME基因的突变会导致线粒体DNA大量逃逸到细胞核。yme1 yme2酵母菌株的合成呼吸生长缺陷可被YNT20中的隐性突变抑制。YNT20的失活会造成冷敏感型呼吸生长缺陷，在yme1背景中更明显，且可被yme2抑制。YNT20的失活会使yme1菌株（而非yme2菌株）中线粒体DNA逃逸速率出现定性降低，这表明YNT20在yme1介导的线粒体DNA逃逸途径中发挥作用。YNT20p是一种可溶性线粒体蛋白，属于假定的3'-5'核酸外切酶亚家族。此外，Yme2p中的保守序列元件表明该蛋白可能也作为核酸外切酶发挥作用。
