Nelson D W, Linning R M, Davison P J, Honda B M
IMBB and Department of Biological Sciences, Simon Fraser University, Burnaby, BC V5A 1S6, Canada.
Gene. 1998 Sep 18;218(1-2):9-16. doi: 10.1016/s0378-1119(98)00392-8.
In the nematode C. elegans, we had previously observed apparent species specificity in 5S RNA transcription. We have now undertaken a further study of 5S RNA gene transcription in this organism and in the related nematode, C. briggsae; the latter was chosen because it might show evolutionarily conserved, functionally important features. Deletion mutagenesis and transcription in vitro, followed by more precise replacements of short blocks of 5' sequence, show that a short, TATA-like sequence at -25 is essential for efficient transcription in vitro of the 1.0-kb C. elegans 5S DNA repeat, and of both C. briggsae 0.7- and 1.0-kb 5S DNA repeats. Internal sequences within the 5S RNA gene appear to be required and can compete for limiting transcription components, whereas 5' flanking sequences do not. These observations suggest that the process of 5S RNA transcription is similar in these nematodes and other higher eukaryotes.
在秀丽隐杆线虫中，我们之前观察到5S RNA转录存在明显的物种特异性。我们现在对该生物体以及相关线虫——嗜热栖热放线菌中的5S RNA基因转录进行了进一步研究；选择后者是因为它可能展现出进化上保守的、功能重要的特征。缺失诱变和体外转录，随后对短的5'序列片段进行更精确的替换，结果表明，位于-25处的一个短的、类似TATA的序列对于1.0 kb的秀丽隐杆线虫5S DNA重复序列以及嗜热栖热放线菌0.7 kb和1.0 kb的5S DNA重复序列在体外的高效转录至关重要。5S RNA基因内部的序列似乎是必需的，并且能够竞争有限的转录成分，而5'侧翼序列则不然。这些观察结果表明，这些线虫和其他高等真核生物中5S RNA转录过程是相似的。
