DNA SEQUENCE CHARACTERIZATION OF BACTERIOPHAGE T4 RII MUTATIONS

我们使用噬菌体T4 rII系统作为模型来探索 DNA损伤和诱变的机制。 因为传统的DNA 用于分析rII分子性质的测序方法 突变是费力和缓慢的，我们正在开发基于 基因组测序和/或聚合酶链反应方法 序列扩增。 然后，重要的突变类型 将检查它们的序列变化。 例如，即使 温和的热量会破坏DNA，如果不进行修复， 每个二倍体人类细胞每天大约有100个突变。 早期的研究表明，热诱导转换， 在噬菌体T4中G：C碱基对的颠换。 遗传研究 表明热诱导颠换的主要途径是G：C 导致C：G，但不排除G：C导致A：T， 可以通过测序研究容易地解决区别。

We are using the bacteriophage T4 rII system as a model to explore mechanisms of DNA damage and mutagenesis. Because traditional DNA sequencing methods for analyzing the molecular nature of rII mutations are laborious and slow, we are developing methods based on genomic sequencing and/or the polymerase-chain-reaction method of sequence amplification. Then, important classes of mutations will be examined for their sequence changes. For instance, even mild heat damages DNA and could, if uncountered by repair, produce on the order of 100 mutations per diploid human cell per day. Earlier studies showed that heat induces both transitions and transversions at G:C base pairs in phage T4. Genetic studies suggested that the main heat-induced transversion pathway is G:C leads to C:G but did not exclude G:C leads to A:T, and the distinction can be easily resolved by sequencing studies.