Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309, USA.
Mol Cell Biol. 2010 Apr;30(8):1937-45. doi: 10.1128/MCB.01370-09. Epub 2010 Feb 12.
The ancient MYH7b gene, expressed in striated muscle and brain, encodes a sarcomeric myosin and the intronic microRNA miR-499. We find that skipping of an exon introduces a premature termination codon in the transcript that downregulates MYH7b protein production without affecting microRNA expression. Among other genes, endogenous miR-499 targets the 3' untranslated region of the transcription factor Sox6, which in turn acts as a repressor of MYH7b transcriptional activity. Thus, concerted transcription and alternative splicing uncouple the level of expression of MYH7b and miR-499 when their coexpression is not required.
古老的 MYH7b 基因在横纹肌和大脑中表达，编码一个肌球蛋白和内含子 microRNA miR-499。我们发现，外显子的跳过会在转录本中引入一个过早终止密码子，从而下调 MYH7b 蛋白的产生，而不影响 microRNA 的表达。在其他基因中，内源性 miR-499 靶向转录因子 Sox6 的 3'非翻译区，而 Sox6 反过来又作为 MYH7b 转录活性的抑制剂。因此，当不需要它们的共表达时，协同转录和选择性剪接会使 MYH7b 和 miR-499 的表达水平解耦。
