Zakian V A
Proc Natl Acad Sci U S A. 1981 May;78(5):3128-32. doi: 10.1073/pnas.78.5.3128.
A specific fraction of chromosomal DNA from both yeast and a wide variety of other eukaryotes, but not from Escherichia coli, promotes high-frequency transformation in yeast. The plasmids containing these sequences are maintained as extra-chromosomal molecules in transformed cells. These results suggest that similar or identical sequences are used for the initiation of DNA replication in eukaryotes. To test this hypothesis, several foreign eukaryotic DNAs implicated directly or indirectly in the initiation of DNA replication have been examined for their ability to promote autonomous, extrachromosomal replication in yeast. Simian virus 40 DNA, amplified Xenopus laevis ribosomal DNA, X. laevis 5S ribosomal DNA, X. laevis mtDNA, and five different members of the Alu I family of human middle repetitive DNAs were cloned into the vector YIp5 and used to transform yeast. Of these DNAs, only Xenopus mtDNA promoted high-frequency transformation and extrachromosomal maintenance of YIp5 DNA. A 2.2-kilobase EcoRI fragment from the 17.4-kilobase mtDNA molecule was responsible for these activities. This fragment contains the sequence used for the initiation of replication in Xenopus mitochondria.
来自酵母和多种其他真核生物而非大肠杆菌的特定染色体DNA片段，可促进酵母中的高频转化。含有这些序列的质粒在转化细胞中作为染色体外分子维持。这些结果表明，真核生物中DNA复制起始使用了相似或相同的序列。为了验证这一假设，已对几种直接或间接参与DNA复制起始的外源真核DNA进行了检测，以考察它们促进酵母自主染色体外复制的能力。将猴病毒40 DNA、扩增的非洲爪蟾核糖体DNA、非洲爪蟾5S核糖体DNA、非洲爪蟾线粒体DNA以及人类中度重复DNA的Alu I家族的五个不同成员克隆到载体YIp5中，并用于转化酵母。在这些DNA中，只有非洲爪蟾线粒体DNA促进了YIp5 DNA的高频转化和染色体外维持。来自17.4千碱基线粒体DNA分子的一个2.2千碱基的EcoRI片段负责这些活性。该片段包含非洲爪蟾线粒体中用于复制起始的序列。
