A test of the transcription model for biased inheritance of yeast mitochondrial DNA.
A test of the transcription model for biased inheritance of yeast mitochondrial DNA.
复制标题
酵母线粒体 DNA 偏向遗传转录模型的测试。
DOI：
10.1128/mcb.15.9.4803
复制
发表时间：
1995
影响因子：
5.3
通讯作者：
Fangman,WL
中科院分区：
文献类型：
--
作者：
Lorimer,HE;Brewer,BJ;Fangman,WL
哺乳动物线粒体 DNA (mtDNA) 复制似乎需要两个链特异性复制起点。在酿酒酵母 DNA 的重复序列中发现了这些起源的结构等同物。这些惊人的相似性促成了 mtDNA 复制起始的通用模型，其中通过切割起始区域转录物产生引物。与该模型一致的是具有高密度重复 (HS [rho2]) 的酵母 mtDNA ([rho2]) 缺失突变体的特性。这些突变 mtDNA 优先由 HS [rho2] 细胞与含有野生型 mtDNA ([rho1]) 的细胞交配产生的后代遗传。这种偏差被认为是由于作为起点的高密度重复序列赋予 HS [rho2] mtDNA 复制优势。为了测试转录是否确实是 HS [rho2] mtDNA 优先遗传所必需的，我们删除了线粒体 RNA 聚合酶的核基因 (RPO41)，将转录物减少了至少 1000 倍。由于删除 RPO41 后，[rho2] 基因组稳定，但 [rho1] 基因组不稳定，因此我们检查了 HS [rho2] 和中性 [rho2] 细胞之间的交配。中性 [rho2] mtDNA 缺乏重复序列，并且不会在 [rho2] 3 [rho1] 杂交中优先遗传。在 HS [rho2] 3 中性 [rho2] 交配中，无论父母均为野生型还是 RPO41 均被删除，HS [rho2] mtDNA 都会优先遗传。因此，来自rep启动子的转录对于偏向遗传来说似乎不是必需的。我们的结果以及对文献的分析表明，转录引发并不是 mtDNA 复制起始的通用机制。
Two strand-specific origins of replication appear to be required for mammalian mitochondrial DNA (mtDNA) replication. Structural equivalents of these origins are found in therepsequences ofSaccharomyces cerevisiaemtDNA. These striking similarities have contributed to a universal model for the initiation of mtDNA replication in which a primer is created by cleavage of an origin region transcript. Consistent with this model are the properties of deletion mutants of yeast mtDNA ([rho2]) with a high density ofreps (HS [rho2]). These mutant mtDNAs are preferentially inherited by the progeny resulting from the mating of HS [rho2] cells with cells containing wild-type mtDNA ([rho1]). This bias is presumed to result from a replication advantage conferred on HS [rho2] mtDNA by the high density ofrepsequences acting as origins. To test whether transcription is indeed required for the preferential inheritance of HS [rho2] mtDNA, we deleted the nuclear gene (RPO41) for the mitochondrial RNA polymerase, reducing transcripts by at least 1000-fold. Since [rho2] genomes, but not [rho1] genomes, are stable whenRPO41is deleted, we examined matings between HS [rho2] and neutral [rho2] cells. Neutral [rho2] mtDNAs lackrepsequences and are not preferentially inherited in [rho2] 3 [rho1] crosses. In HS [rho2] 3 neutral [rho2] matings, the HS [rho2] mtDNA was preferentially inherited whether both parents were wild type or both were deleted forRPO41. Thus, transcription from thereppromoter does not appear to be necessary for biased inheritance. Our results, and analysis of the literature, suggest that priming by transcription is not a universal mechanism for mtDNA replication initiation.