Chambers P, Gingold E
Division of Biological and Environmental Sciences, Hatfield Polytechnic, Herts, UK.
Curr Genet. 1986;10(8):565-71. doi: 10.1007/BF00418122.
Work in recent years has produced indirect evidence to support the view that the phenomenon of suppressiveness in yeast is the result of the ability of the petite mtDNA to out-replicate the wild-type genome. We have developed a method, based on fluorography of gels containing restriction fragments of radioactively labelled zygotic mtDNA, by which it has been possible to follow directly the incorporation of label into the two mtDNA species and hence their relative synthesis. Four petite isolates of 70%, 43%, 23% and 12% suppressiveness were tested by this method in crosses with a grande strain. Only the mtDNA from the 70% suppressive petite showed a replicative advantage over the grande mtDNA. The mtDNA from the 43% and 23% suppressive actually appeared to undergo, if anything, less replication in the zygote than the grande mtDNA. It is concluded that while some petites may exhibit suppressiveness as a result of enhanced replicative efficiency of their mtDNA, this cannot be the explanation for all suppressive petite strains.
近年来的研究工作已产生间接证据，支持这样一种观点：酵母中的抑制现象是由于小菌落线粒体DNA（mtDNA）比野生型基因组具有更强复制能力的结果。我们开发了一种方法，该方法基于对含有放射性标记合子mtDNA限制性片段的凝胶进行荧光自显影，通过这种方法能够直接追踪放射性标记掺入两种mtDNA的情况，从而了解它们的相对合成情况。用这种方法对抑制率分别为70%、43%、23%和12%的四个小菌落分离株与一个大菌落菌株进行杂交测试。只有来自70%抑制性小菌落的mtDNA显示出比大菌落mtDNA具有复制优势。来自43%和23%抑制性小菌落的mtDNA实际上在合子中的复制情况，相比大菌落mtDNA而言，即便有差异也表现为更少的复制。得出的结论是，虽然一些小菌落可能由于其mtDNA复制效率提高而表现出抑制现象，但这并不能解释所有具有抑制性的小菌落菌株。
