Towler Benjamin P, Jones Christopher I, Viegas Sandra C, Apura Patricia, Waldron Joseph A, Smalley Sarah K, Arraiano Cecilia M, Newbury Sarah F
a Brighton and Sussex Medical School; Medical Research Building; University of Sussex; Falmer , Brighton , UK.
RNA Biol. 2015;12(7):728-41. doi: 10.1080/15476286.2015.1040978.
Dis3 is a highly conserved exoribonuclease which degrades RNAs in the 3'-5' direction. Mutations in Dis3 are associated with a number of human cancers including multiple myeloma and acute myeloid leukemia. In this work, we have assessed the effect of a Dis3 knockdown on Drosophila imaginal disc development and on expression of mature microRNAs. We find that Dis3 knockdown severely disrupts the development of wing imaginal discs in that the flies have a "no wing" phenotype. Use of RNA-seq to quantify the effect of Dis3 knockdown on microRNA expression shows that Dis3 normally regulates a small subset of microRNAs, with only 11 (10.1%) increasing in level ≥ 2-fold and 6 (5.5%) decreasing in level ≥ 2-fold. Of these microRNAs, miR-252-5p is increased 2.1-fold in Dis3-depleted cells compared to controls while the level of the miR-252 precursor is unchanged, suggesting that Dis3 can act in the cytoplasm to specifically degrade this mature miRNA. Furthermore, our experiments suggest that Dis3 normally interacts with the exosomal subunit Rrp40 in the cytoplasm to target miR-252-5p for degradation during normal wing development. Another microRNA, miR-982-5p, is expressed at lower levels in Dis3 knockdown cells, while the miR-982 precursor remains unchanged, indicating that Dis3 is involved in its processing. Our study therefore reveals an unexpected specificity for this ribonuclease toward microRNA regulation, which is likely to be conserved in other eukaryotes and may be relevant to understanding its role in human disease.
Dis3是一种高度保守的外切核糖核酸酶，可沿3' - 5'方向降解RNA。Dis3的突变与多种人类癌症相关，包括多发性骨髓瘤和急性髓系白血病。在这项研究中，我们评估了敲低Dis3对果蝇成虫盘发育以及成熟微小RNA表达的影响。我们发现，敲低Dis3会严重破坏翅成虫盘的发育，果蝇表现出“无翅”表型。利用RNA测序来量化敲低Dis3对微小RNA表达的影响，结果显示Dis3通常调节一小部分微小RNA，只有11个（10.1%）水平升高≥2倍，6个（5.5%）水平降低≥2倍。在这些微小RNA中，与对照相比，在Dis3缺失的细胞中miR - 252 - 5p水平升高了2.1倍，而miR - 252前体的水平未发生变化，这表明Dis3可以在细胞质中发挥作用，特异性降解这种成熟的微小RNA。此外，我们的实验表明，在正常翅发育过程中，Dis3通常在细胞质中与外泌体亚基Rrp40相互作用，靶向miR - 252 - 5p进行降解。另一种微小RNA，miR - 982 - 5p，在敲低Dis3的细胞中表达水平较低，而miR - 982前体保持不变，这表明Dis3参与了其加工过程。因此，我们的研究揭示了这种核糖核酸酶在微小RNA调节方面具有意想不到的特异性，这种特异性可能在其他真核生物中保守，并且可能与理解其在人类疾病中的作用相关。
