Jiangsu Key Laboratory for Microbes and Functional Genomics, School of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210023, PR China.
Microbiology (Reading). 2018 Mar;164(3):400-409. doi: 10.1099/mic.0.000602. Epub 2018 Jan 12.
Mitochondrial gene expression is essential for adenosine triphosphate synthesis via oxidative phosphorylation, which is the universal energy currency of cells. Here, we report the identification and characterization of a homologue of Saccharomyces cerevisiae Mtf2 (also called Nam1) in Schizosaccharomyces pombe. The Δmtf2 mutant with the intron-containing mitochondrial DNA (mtDNA) exhibited impaired growth on a rich medium containing the non-fermentable carbon source glycerol, suggesting that mtf2 is involved in mitochondrial function. mtf2 deletion in a mitochondrial intron-containing background resulted in a barely detectable level of the cox1 mRNA and a reduction in the level of the cob1 mRNA, and severely impaired cox1 translation. In contrast, mtf2 deletion in a mitochondrial intron-less background did not affect the levels of cox1 and cob1 mRNAs. However, Cox1 synthesis could not be restored to the control level in the Δmtf2 mutant with intron-less mtDNA. Our results suggest that unlike its counterpart in S. cerevisiae which plays a general role in synthesis of mtDNA-encoded proteins, S. pombe Mtf2 primarily functions in cox1 translation and the effect of mtf2 deletion on splicing of introns in mtDNA is likely due to a deficiency in the synthesis of intron-encoded maturases.
线粒体基因表达对于通过氧化磷酸化合成三磷酸腺苷是必不可少的，氧化磷酸化是细胞的通用能量货币。在这里，我们报道了在裂殖酵母中鉴定和表征酿酒酵母 Mtf2（也称为 Nam1）同源物。含有内含子的线粒体 DNA（mtDNA）的Δmtf2 突变体在含有不可发酵碳源甘油的丰富培养基上生长受到损害，这表明 mtf2 参与线粒体功能。在含有线粒体内含子的背景下缺失 mtf2 会导致 cox1 mRNA 的水平几乎检测不到，并降低 cob1 mRNA 的水平，并严重抑制 cox1 的翻译。相比之下，在没有线粒体内含子的背景下缺失 mtf2 不会影响 cox1 和 cob1 mRNA 的水平。然而，在没有内含子的 mtDNA 的Δmtf2 突变体中，Cox1 的合成不能恢复到对照水平。我们的结果表明，与在酿酒酵母中发挥普遍作用的同工酶不同，裂殖酵母 Mtf2 主要在 cox1 翻译中发挥作用，mtf2 缺失对 mtDNA 内含子剪接的影响可能是由于内含子编码成熟酶的合成不足所致。
