Melton D W, McEwan C, McKie A B, Reid A M
Cell. 1986 Jan 31;44(2):319-28. doi: 10.1016/0092-8674(86)90766-x.
The mouse hypoxanthine phosphoribosyltransferase gene, like several other housekeeping genes, lacks many of the features associated with promoters of RNA polymerase II-transcribed genes. HPRT transcripts have multiple initiation sites and an HPRT minigene was used to show that only 49 bases of 5' flanking sequence was necessary for normal expression in cultured cells. The essential region, which occurs within a complex series of direct repeats, is homologous to sequences upstream of other housekeeping genes. When this sequence was deleted, cryptic upstream initiation sites were revealed. Similar aberrant patterns of initiation were seen with all minigenes assayed in Xenopus oocytes. We speculate that this region of the HPRT promoter is involved in a different interaction with the transcriptional machinery to that occurring at more conventional promoters.
小鼠次黄嘌呤磷酸核糖转移酶基因与其他几个管家基因一样，缺乏许多与RNA聚合酶II转录基因启动子相关的特征。HPRT转录本有多个起始位点，一个HPRT小基因被用于证明在培养细胞中正常表达仅需5'侧翼序列的49个碱基。关键区域存在于一系列复杂的直接重复序列中，与其他管家基因上游的序列同源。当该序列被删除时，隐藏的上游起始位点被揭示出来。在非洲爪蟾卵母细胞中检测的所有小基因都出现了类似的异常起始模式。我们推测，HPRT启动子的这个区域与转录机制的相互作用不同于在更传统启动子处发生的相互作用。
