Muhich M L, Hsu M P, Boothroyd J C
Department of Microbiology and Immunology, Stanford University School of Medicine, CA 94305-5402.
Gene. 1989 Oct 15;82(1):169-75. doi: 10.1016/0378-1119(89)90042-5.
The synthesis of most, if not all, mRNA in trypanosomes involves the splicing in trans of two RNA molecules. One of these includes the common 5' mini-exon or spliced-leader sequence, while the other contains the complete protein-coding exon sequence for a given gene. We have recently shown that trans-splicing of tubulin transcripts is disrupted by heat shock, whereas trans-splicing of Hsp70 mRNA continues unabated, despite the increased expression of this latter gene [Muhich and Boothroyd, Mol. Cell Biol. 8 (1988) 3837-3846]. In this report we show that, in addition to being polyadenylated, the dimeric beta-alpha tubulin transcripts which accumulate as a result of heat shock have a correctly processed 5'-end (through mini-exon addition), and that the extent of disruption is proportional to the degree of heat shock. We further show that mRNA levels for two evolutionarily-conserved heat-shock proteins, Hsp70 and Hsp85, are increased under the splicing-disruptive conditions of heat shock.
锥虫中大多数（即便不是全部）mRNA的合成涉及两个RNA分子的反式剪接。其中一个包含常见的5' 小外显子或剪接前导序列，而另一个则包含给定基因的完整蛋白质编码外显子序列。我们最近发现，热休克会破坏微管蛋白转录本的反式剪接，而Hsp70 mRNA的反式剪接则不受影响，尽管该基因的表达有所增加[穆希奇和布思罗伊德，《分子细胞生物学》8 (1988) 3837 - 3846]。在本报告中，我们表明，除了被聚腺苷酸化外，热休克导致积累的二聚体β-微管蛋白-α微管蛋白转录本具有正确加工的5' 端（通过添加小外显子），并且破坏程度与热休克的程度成正比。我们还进一步表明，在热休克导致剪接破坏的条件下，两种进化保守的热休克蛋白Hsp70和Hsp85的mRNA水平会升高。
