Mauro V P, Edelman G M
Department of Neurobiology, Scripps Research Institute, La Jolla, CA, USA.
Proc Natl Acad Sci U S A. 1997 Jan 21;94(2):422-7. doi: 10.1073/pnas.94.2.422.
Many eukaryotic mRNAs contain sequences that resemble segments of 28S and 18S rRNAs, and these rRNA-like sequences are present in both the sense and antisense orientations. Some are similar to highly conserved regions of the rRNAs, whereas others have sequence similarities to expansion segments. In particular, four 18S rRNA-like sequences are found in several hundred different genes, and the location of these four sequences within the various genes is not random. One of these rRNA-like sequences is preferentially located within protein coding regions immediately upstream of the termination codon of a number of genes. Northern blot analysis of poly(A)+ RNA from different vertebrates (chicken, cattle, rat, mouse, and human) revealed that a large number of discrete RNA molecules hybridize at high stringency to cloned probes prepared from the 28S or 18S rRNA sequences that were found to match those in mRNAs. Inhibition of polymerase II activity, which prevents the synthesis of most mRNAs, abolished most of the hybridization to the rRNA probes. We consider the hypotheses that rRNA-like sequences may have spread throughout eukaryotic genomes and that their presence in primary transcripts may differentially affect gene expression.
许多真核生物的mRNA含有类似于28S和18S rRNA片段的序列，这些rRNA样序列以正义和反义方向存在。一些与rRNA的高度保守区域相似，而另一些与扩展片段具有序列相似性。特别地，在数百个不同基因中发现了四个18S rRNA样序列，并且这四个序列在各个基因中的位置并非随机。这些rRNA样序列之一优先位于许多基因终止密码子上游紧邻的蛋白质编码区域内。对来自不同脊椎动物（鸡、牛、大鼠、小鼠和人类）的聚腺苷酸加尾RNA进行的Northern印迹分析表明，大量离散的RNA分子在高严谨度下与从28S或18S rRNA序列制备的克隆探针杂交，这些序列被发现与mRNA中的序列匹配。抑制聚合酶II活性（这会阻止大多数mRNA的合成）消除了与rRNA探针的大部分杂交信号。我们考虑这样的假说：rRNA样序列可能已遍布真核生物基因组，并且它们在初级转录本中的存在可能会对基因表达产生不同的影响。
