Latini Claudia, Eichlinger Julian, Fuchs Anna-Lisa, Zhai Si-Nan, Ho-Xuan Hung, Lehmann Gerhard, Glažar Petar, Rajewsky Nikolaus, Bruckmann Astrid, Yang Li, Sprangers Remco, Meister Gunter
Regensburg Center for Biochemistry (RCB), Laboratory for RNA Biology, University of Regensburg, 94053 Regensburg, Germany.
Regensburg Center for Biochemistry (RCB), Institute of Biophysics and Physical Biochemistry, University of Regensburg, 93053 Regensburg, Germany.
Cell Rep. 2025 Jun 24;44(6):115769. doi: 10.1016/j.celrep.2025.115769. Epub 2025 May 28.
The ribonuclease DIS3 interacts through its PIN domain with the nuclear exosome and degrades linear RNA substrates using its exoribonuclease domain. However, the PIN domain is also an active endoribonuclease, but cellular substrates are largely unknown. Here, we use a biochemical strategy to find ribonucleases that could degrade circular RNAs (circRNAs). Due to the lack of accessible ends, circRNAs are resistant to exonucleolytic cleavage and are thus more stable than linear RNAs. Using biochemical assays, we identify DIS3 as a candidate for circRNA degradation and demonstrate that it partially resides in the cytoplasm, where circRNAs are degraded. DIS3 shows cleavage activity toward a number of circRNAs and functions independently of the exosome core in vitro. Upon knockdown of DIS3 in cell lines, selected circRNAs are moderately stabilized. We thus propose that cytoplasmic DIS3 functions as a stand-alone enzyme independently of the exosome core and may contribute to circRNA turnover.
核糖核酸酶DIS3通过其PIN结构域与核外泌体相互作用，并利用其核糖核酸外切酶结构域降解线性RNA底物。然而，PIN结构域也是一种活性核糖核酸内切酶，但其细胞底物在很大程度上尚不清楚。在这里，我们采用一种生化策略来寻找能够降解环状RNA（circRNA）的核糖核酸酶。由于缺乏可接近的末端，circRNA对外切核酸酶切割具有抗性，因此比线性RNA更稳定。通过生化分析，我们确定DIS3是circRNA降解的候选者，并证明它部分存在于circRNA被降解的细胞质中。DIS3对多种circRNA具有切割活性，并且在体外独立于外泌体核心发挥作用。在细胞系中敲低DIS3后，选定的circRNA会适度稳定。因此，我们提出细胞质中的DIS3作为一种独立于外泌体核心的酶发挥作用，可能有助于circRNA的周转。
