RNA TRANSCRIPTS INDUCED BY HYPERTHERMIA IN RODENT CELLS

原核细胞和真核细胞对环境的响应 应激是通过诱导各种与应激相关的蛋白质来实现的。在……里面 哺乳动物细胞，最具特征的应激群体 蛋白质是由高温诱导的。热的转录 休克蛋白在高温后显著升高， 其中几个基因已经从HeLa细胞中克隆出来 实验室。其他基因的转录很可能也是 在哺乳动物细胞中诱导，因为大约有10-20个基因是 在原核生物和低等真核生物中诱导。一种方法是 分离这样的转录本是为了丰富热休克的特异性 通过与对照的mRNA杂交消减的方法获得cDNAs 细胞。我们已经在啮齿动物细胞V79上做到了这一点，我们还 构建了热休克处理(HS)细胞的cDNA文库。 我们的结果表明，最丰富的转录本诱导了 HS在V79和CHO细胞系中是一种重复的小基因 元素。对cDNA系的序列分析表明它们 是啮齿动物B2的短RNA聚合酶III转录本 重复元素。这种重复元件的转录有 先前发现在转化的啮齿动物细胞中增加 和啮齿动物肿瘤细胞。有趣的是，HS蛋白是 通常在转化的细胞中升高。这个B2的功能 RNA是未知的，但它是多聚腺苷化的，定位于 细胞质；它可能在翻译的调节中起到一定作用。 这一假设得到了我们的观察支持，即不同的 B2转录物的光谱在热休克后被转录。 热冲击对翻译有深远的影响；例如，优先 热休克蛋白RNA的翻译。 我们还发现，热休克诱导的B2RNA 与大热的诱导暂时相关 休克蛋白核糖核酸。

Prokaryotic and euklaryotic cells respond to environmental stress by the induction of a variety of stress-related proteins. In mammalian cells, the most well characterized group of stress proteins are induced by hyperthermia. Transcription of heat shock proteins increases markedly after hyperthermia and several of these genes have been cloned from HeLa cells in other laboratories. It is likely that transcription of other genes is also induced in mammalian cells since approximately 10-20 genes are induced in prokaryotes and lower eukaryotes. One approach to isolate such transcripts is to enrich for heat shock specific cDNA's by hybridization subtraction with mRNA from control cells. We have done this with rodent cells, V79, and we have also constructed a cDNA library from heat shock treated (HS) cells. Our results indicate that the most abundant transcript induced by HS in V79 and CHO cell lines is a small repetitive genetic element. Sequence analysis of cDNA lines revealed that they were short RNA polymerase III transcripts of the rodent B2 repetitive element. Transcription of this repetitive element has previously been found to be increased in transformed rodent cells and rodent tumor cells. It is of interest that HS proteins are usually elevated in transformed cells. The function of this B2 RNA is unknown, but it is polyadenylated with localization to the cytoplasm; it may play some role in the regulation of translation. This hypothesis is supported by our observation that a different spectrum of B2 transcripts are transcribed after heat shock. Heat shock has profound effects on translation; e.g., preferential translation of heat shock protein RNA. We have also found that the induction of B2 RNA by heat shock correlated temporarily with the induction of the major heat shock protein RNA's.