Lavia P, Macleod D, Bird A
MRC Mammalian Genome Unit, Edinburgh, Scotland, UK.
EMBO J. 1987 Sep;6(9):2773-9. doi: 10.1002/j.1460-2075.1987.tb02572.x.
We determined the nucleotide sequence of two HTF islands that were selected at random from mouse chromosomal DNA. Both were non-methylated, G + C rich, and contained CpG at close to the expected frequency. When used as probes, the two islands detected multiple transcripts in RNA from several mouse tissues. Cloned cDNAs for the major transcripts of one island (HTF9) were isolated and used to construct a transcriptional map. We found that HTF9 contains the origin of a pair of divergent transcripts that are probably messenger RNAs. The bidirectional promoter is different from those previously observed as the major transcription start sites for each orientation are coincident on opposite strands of the DNA. The results support the view that HTF islands often mark genes, and they suggest that bidirectional transcription may be a common feature of island promoters.
我们测定了从小鼠染色体DNA中随机选取的两个HTF岛的核苷酸序列。二者均未甲基化，富含G + C，且所含的CpG频率接近预期。当用作探针时，这两个岛在来自几种小鼠组织的RNA中检测到多个转录本。分离出一个岛（HTF9）主要转录本的克隆cDNA，并用于构建转录图谱。我们发现HTF9包含一对可能是信使RNA的反向转录本的起始位点。双向启动子与先前观察到的不同，因为每个方向的主要转录起始位点在DNA的相反链上是重合的。这些结果支持了HTF岛常常标记基因的观点，并且表明双向转录可能是岛启动子的一个共同特征。
