The Bicoid Stability Factor Controls Polyadenylation and Expression of Specific Mitochondrial mRNAs in Drosophila melanogaster
The Bicoid Stability Factor Controls Polyadenylation and Expression of Specific Mitochondrial mRNAs in Drosophila melanogaster
复制标题
DOI：
10.1371/journal.pgen.1002324
复制
发表时间：
2011-10-01
期刊：
影响因子：
4.5
通讯作者：
Larsson, Nils-Goeran
中科院分区：
文献类型：
--
作者：
Bratic, Ana;Wredenberg, Anna;Larsson, Nils-Goeran
黑腹果蝇的bicoid稳定因子（BSF）被报道存在于细胞质中，在那里它稳定母体贡献的bicoid mRNA并结合从早期合子基因表达的mRNA。BSF也可能有其他作用，因为它是普遍表达和成年苍蝇的生存所必需的。我们已经进行了免疫荧光和细胞分级分离分析，并在这里显示，BSF主要是一个线粒体蛋白。我们研究了两个独立的RNAi敲低果蝇品系，并报告BSF蛋白水平降低导致严重的呼吸缺陷和晚期幼虫阶段的发育延迟。BSF的普遍敲除导致特定线粒体mRNA的多腺苷酸化尾长度的严重减少，伴随着未加工的多顺反子RNA中间体的富集。此外，我们观察到mRNA稳态水平显着降低，尽管从头转录增加。令人惊讶的是，线粒体从头翻译增加，异常的线粒体翻译产物存在于敲低果蝇中，这表明BSF除了在mRNA成熟和稳定性中的作用外，还在协调线粒体翻译中发挥作用。因此，我们报告了一种新的功能，BSF在苍蝇，并证明它有一个重要的线粒体内的作用，这是必不可少的维持mtDNA基因表达和氧化磷酸化。
The bicoid stability factor (BSF) of Drosophila melanogaster has been reported to be present in the cytoplasm, where it stabilizes the maternally contributed bicoid mRNA and binds mRNAs expressed from early zygotic genes. BSF may also have other roles, as it is ubiquitously expressed and essential for survival of adult flies. We have performed immunofluorescence and cell fractionation analyses and show here that BSF is mainly a mitochondrial protein. We studied two independent RNAi knockdown fly lines and report that reduced BSF protein levels lead to a severe respiratory deficiency and delayed development at the late larvae stage. Ubiquitous knockdown of BSF results in a severe reduction of the polyadenylation tail lengths of specific mitochondrial mRNAs, accompanied by an enrichment of unprocessed polycistronic RNA intermediates. Furthermore, we observed a significant reduction in mRNA steady state levels, despite increased de novo transcription. Surprisingly, mitochondrial de novo translation is increased and abnormal mitochondrial translation products are present in knockdown flies, suggesting that BSF also has a role in coordinating the mitochondrial translation in addition to its role in mRNA maturation and stability. We thus report a novel function of BSF in flies and demonstrate that it has an important intra-mitochondrial role, which is essential for maintaining mtDNA gene expression and oxidative phosphorylation.