Voelkel-Meiman K, Keil R L, Roeder G S
Cell. 1987 Mar 27;48(6):1071-9. doi: 10.1016/0092-8674(87)90714-8.
A DNA sequence (HOT1) from the repeated ribosomal RNA gene cluster of Saccharomyces cerevisiae can stimulate genetic exchange when inserted at novel locations in the yeast genome. Localization of the sequences required for HOT1 activity demonstrates that two noncontiguous fragments of DNA are required for the stimulation of recombination. One of these fragments contains the transcription initiation site for the major 35S ribosomal RNA precursor. The other contains an enhancer of RNA polymerase I transcription. We suggest that transcription by RNA polymerase I initiating in the inserted rDNA and proceeding through the adjacent sequences is responsible for the stimulation of exchange. Consistent with this interpretation, insertion of the putative termination site for RNA polymerase I transcription between HOT1 and the adjacent recombining DNA abolishes the recombination stimulation. Transcription through both copies of the homologous recombining sequences appears to be necessary for enhanced exchange.
来自酿酒酵母重复核糖体RNA基因簇的一段DNA序列（HOT1），当插入酵母基因组的新位置时，能够刺激基因交换。对HOT1活性所需序列的定位表明，刺激重组需要两个不相邻的DNA片段。其中一个片段包含主要35S核糖体RNA前体的转录起始位点。另一个包含RNA聚合酶I转录的增强子。我们认为，RNA聚合酶I在插入的核糖体DNA中起始并通过相邻序列进行转录，这是刺激交换的原因。与这一解释一致的是，在HOT1和相邻的重组DNA之间插入RNA聚合酶I转录的假定终止位点会消除重组刺激。通过同源重组序列的两个拷贝进行转录似乎是增强交换所必需的。
