Williams T, Fried M
Nature. 1986;322(6076):275-9. doi: 10.1038/322275a0.
The organization and large size of the mammalian cell genome allows spatial separation of different transcription units. In those cases where more than one species of messenger are synthesized from the same cellular DNA sequence, they have been found to be generated from transcription proceeding in the same direction. These mRNAs always share regions of homology and can differ from one another as a result of differential processing (splicing and/or polyadenylation) or alternative initiation. In contrast, complementary mRNAs transcribed from opposite strands of the same cellular DNA sequence have not previously been observed. Here we have identified a region of mouse DNA at which processed mRNAs from two adjacent convergent transcription units overlap by 133 base pairs (bp) at their 3'-untranslated ends. One of the transcription units appears to encode a second mRNA which does not contain this overlapping region. This represents the first description of the natural occurrence of processed mammalian cell mRNAs transcribed from opposite strands of the same DNA sequence. The implications of these complementary regions in normal gene regulation are discussed in the context of the finding that the artificial introduction into cells of DNA constructs synthesizing anti-sense RNAs complementary to regions of mRNA transcribed from a chromosomal gene, can inhibit the gene's activity, presumably by the formation of double-stranded RNA.
哺乳动物细胞基因组的组织结构和庞大体积使得不同转录单元能够在空间上分离。在从同一细胞DNA序列合成不止一种信使RNA的情况下，人们发现它们是由同一方向进行的转录产生的。这些信使RNA总是共享同源区域，并且由于差异加工（剪接和/或聚腺苷酸化）或可变起始而彼此不同。相比之下，以前从未观察到从同一细胞DNA序列的相反链转录而来的互补信使RNA。在这里，我们在小鼠DNA中鉴定出一个区域，来自两个相邻的会聚转录单元的加工信使RNA在其3'非翻译末端重叠了133个碱基对（bp）。其中一个转录单元似乎编码了一种不包含此重叠区域的第二种信使RNA。这是对从同一DNA序列的相反链转录而来的加工哺乳动物细胞信使RNA自然发生情况的首次描述。鉴于发现将合成与从染色体基因转录的信使RNA区域互补的反义RNA的DNA构建体人工导入细胞中可以抑制基因活性，推测是通过形成双链RNA，本文讨论了这些互补区域在正常基因调控中的意义。
