Fizikova A Iu, Padkina M V, Sambuk E V
Genetika. 2009 Jun;45(6):745-52.
The cyclin-dependent protein kinase Pho85 is involved in the regulation of phosphate metabolism in yeast Saccharomyces cerevisiae. Mutations in the PH085 gene lead to constitutive synthesis of Pho5 acidic phosphatase, a delay in cell growth on media containing nonfermentable carbon sources, and other pleiotropic effects. In this work, it was shown that the accumulation of respiratory incompetent cells occurs with high frequency in strains carrying pho85 mutations as early as during the first cell divisions, and the number of these cells at the early logarithmic growth phase of the culture promptly reaches virtually 100%. Cytological analysis revealed a high accumulation rate of [rho(0)] cells the background of gene pho85 that may be related to disturbances in the distribution of mitochondrial nucleoids rather than to changes in morphology of mitochondria and a delay in their transport into the bud. Genetic analysis revealed that the appearing secondary mutations pho4, pho81, pho84, and pho87 stabilize nucleoids and hamper the loss of mitochondrial DNA caused by pho85. These results provide evidence for the influence of intracellular phosphate concentration on the inheritance of mitochondrial nucleoids, but it is fully probable that the occurrence of mutation pho4 in the background of gene pho85 may change the expression level of other genes required for the stabilization of mitochondrial functions.
细胞周期蛋白依赖性蛋白激酶Pho85参与酿酒酵母中磷酸盐代谢的调控。PH085基因的突变会导致Pho5酸性磷酸酶的组成型合成，在含有非发酵碳源的培养基上细胞生长延迟，以及其他多效性效应。在这项研究中，结果表明，携带pho85突变的菌株早在第一次细胞分裂期间就高频出现呼吸功能不全细胞的积累，并且在培养物的对数生长早期这些细胞的数量迅速达到几乎100%。细胞学分析显示，在pho85基因背景下[rho(0)]细胞的积累率很高，这可能与线粒体核质分布的紊乱有关，而不是与线粒体形态的变化以及线粒体向芽中的运输延迟有关。遗传分析表明，出现的二次突变pho4、pho81、pho84和pho87可稳定核质并阻碍由pho85引起的线粒体DNA丢失。这些结果为细胞内磷酸盐浓度对线粒体核质遗传的影响提供了证据，但完全有可能在pho85基因背景下pho4突变的出现可能会改变稳定线粒体功能所需的其他基因的表达水平。
