ZRANB3、SMARCAL1與HLTF皆屬於在複製壓力時會促進複製叉反轉的轉位酶，反向複製叉結構不僅可以在有複製壓力時保護停滯的複製叉避免其崩毀，也會使複製速度變慢。然而，在有DNA損傷時，這些轉位酶是單獨運作還是共同運作仍是不明瞭的，故而在本次實驗中，我們嘗試將兩種轉位酶剔除，產生HLTF SMARCAL1及HLTF ZRANB3的雙重剔除的細胞株，並測試DNA損傷試劑cisplatin、methyl methanesulfonate (MMS) 和4-Nitroquinoline 1-oxide (4NQO) 對細胞存活能力的影響。除此之外，我們也測試了以MMS誘導複製壓力時對複製進程的影響，我們發現，與HLTF單獨剔除的細胞相比，同時將HLTF與SMARCAL1剔除的細胞，不管在有或無MMS處理的情況下，其複製進程皆會有明顯的減弱。然而，這樣的結果仍續以更多實驗去驗證。

ZRANB3, SMARCAL1 and HLTF are translocases that promote fork reversal during replication stress. The reversed fork structure not only protect stalled forks from collapse, but also contribute to replication slowing during replication stress. However, it still not clear whether these translocases act alone or work together to respond various types of DNA lesions. In this study, we tried to deplete two translocases by generating HLTF SMARCAL1 and HLTF ZRANB3 double gene-depleted cells. We determined cell survival in respond to various DNA damaging agents including cisplatin, methyl methanesulfonate (MMS), and 4-Nitroquinoline 1-oxide (4NQO). Additionally, we determined progression of replication in response to MMS-induced replication stress. We found that the depletion of HLTF and SMARCAL1 simultaneously further reduced progression of replication both in the absence and presence of MMS, when compared to HLTF-depleted cells. However, more studies will be needed to verify this result.

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