Sekito T, Okamoto K, Kitano H, Yoshida K
Department of Biological Science, Faculty of Science, Hiroshima University, Japan.
Curr Genet. 1995 Jun;28(1):39-53. doi: 10.1007/BF00311880.
The complete 27,694-bp mitochondrial (mt) DNA sequence of Hansenula wingei, which is a typical budding yeast and contains circular mitochondrial DNA, has been determined. The mt sequence contains genes encoding large and small ribosomal RNAs, 25 tRNAs, three subunits of cytochrome c oxidase (subunits 1, 2 and 3), three subunits of ATPase (subunits 6, 8 and 9), apocytochrome b, seven subunits of NADH dehydrogenase (subunits 1, 2, 3, 4, 4L, 5 and 6), and a ribosomal protein, VAR1. The VAR1 gene is considered to be a typical yeast type. This is consistent with data on DNA and the deduced amino-acid sequence homology comparisons of genes ubiquitous in yeast and fungi. However, we have identified seven genes encoding NADH dehydrogenase subunits, which are not found in other yeast mitochondrial genomes, thus placing the H. wingei mitochondrial genome in a unique position. In addition the H. wingei mitochondrial genome also encodes one tRNA pseudogene and one short unidentified ORF. The genome is compact with only two introns both of which contain an ORF. One intron lies in the large rRNA gene while the other is situated in the cytochrome c oxidase subunit-1 gene. The conserved nonanucleotide motif (A/T)TATAAG (T/A)(A/T), which is a transcription start signal in Saccharomyces cerevisiae mitochondria, has also been found in the H. wingei mitochondrial genome. The codon assignments for ATA and CTN in H. wingei mitochondria are different from those in S. cerevisiae mitochondria. These results indicate a unique and novel structure for the H. wingei mitochondrial genome in terms of characteristics which are typical for both yeast and for filamentous fungi. This is the first complete mt DNA sequence report in yeast.
已经测定了典型的出芽酵母汉逊酵母（Hansenula wingei）完整的27,694碱基对线粒体（mt）DNA序列，其线粒体DNA呈环状。该mt序列包含编码大、小核糖体RNA、25种tRNA、细胞色素c氧化酶的三个亚基（亚基1、2和3）、ATP酶的三个亚基（亚基6、8和9）、脱辅基细胞色素b、NADH脱氢酶的七个亚基（亚基1、2、3、4、4L、5和6）以及一种核糖体蛋白VAR1的基因。VAR1基因被认为是典型的酵母类型。这与酵母和真菌中普遍存在的基因的DNA数据以及推导的氨基酸序列同源性比较结果一致。然而，我们鉴定出了七个编码NADH脱氢酶亚基的基因，这些基因在其他酵母线粒体基因组中未被发现，从而使汉逊酵母线粒体基因组处于独特的位置。此外，汉逊酵母线粒体基因组还编码一个tRNA假基因和一个短的未鉴定开放阅读框。该基因组很紧凑，只有两个内含子，且两个内含子都包含一个开放阅读框。一个内含子位于大rRNA基因中，另一个位于细胞色素c氧化酶亚基1基因中。在汉逊酵母线粒体基因组中也发现了保守的九核苷酸基序（A/T）TATAAG（T/A）（A/T），它是酿酒酵母线粒体中的转录起始信号。汉逊酵母线粒体中ATA和CTN的密码子分配与酿酒酵母线粒体中的不同。这些结果表明，就酵母和丝状真菌的典型特征而言，汉逊酵母线粒体基因组具有独特而新颖的结构。这是酵母中首个完整的mt DNA序列报告。
