TERRA, POT1和CST complex在細胞週期的調控

Abstract

端粒是保護基因組完整性的重要結構。適當的端粒維護對於保持端粒功能和防止癌症形成至關重要。TERRA 是一種從次端粒至端粒區域轉錄出的長鏈非編碼 RNA，與端粒維護相關，但其作用仍不清楚。先前的研究表明，TERRA 與 POT1 和 CST 複合物有顯著的相互作用，而這些在細胞周期中的端粒維護中起著不同的作用。因此，我研究了 TERRA、POT1 和 CST 複合物在細胞周期中的調控。通過流式細胞儀和細胞周期分類模型進行了細胞周期判定，細胞周期分類模型以作單細胞細胞周期判定。研究結果顯示，TERRA 在 S 期，特別是晚 S 期的表達水平很高，而 CST 複合物和 POT1 也在這一階段高度定位於端粒。RNA-protein PLA 結果也顯示，TERRA 與 POT1 或 CST 複合物在晚 S 期有高度相互作用。我們提出的觀點是，TERRA充當CST複合物短暫定位的對接位點。在中/晚S期，由於端粒的長度，CST複合物從TERRA轉移到端粒。在G2期，由於TERRA數量的減少，CST複合物定位於端粒，進行 C 鏈填充。

Telomeres are essential structures that protect genome integrity. Proper telomere maintenance is crucial for maintaining telomere function and preventing cancer formation. TERRA, a long non-coding RNA transcribed from the sub-telomeric region, is associated with telomere maintenance, but its role remains elusive. Previous finding indicates that TERRA interacts with POT1 and the CST complex, regulates telomere maintenance in a cell cycle dependent manner. Therefore, I investigated the regulation of TERRA, POT1, and the CST complex during the cell cycle pregression. Cell phase determination was achieved through flow cytometry and a cell phase classification model at the single-cell level. Our findings show that TERRA levels are high in S phase, especially late S phase, while the CST complex and POT1 are also highly localized at telomeres during this phase. RNA-protein PLA also shows a high interaction of TERRA and POT1 or CST complex in late S phase. The proposed argument is that TERRA acts as a docking site for CST complex transient locating. In middle / late S phase, CST complex translocates from TERRA to telomere due to the length of telomere. In G2 phase, CST complex locates at telomere inducing C-strand fill-in due to the decreasing number of TERRA.