Primase promotes the competition between transcription and replication on the same template strand resulting in DNA damage.
Primase promotes the competition between transcription and replication on the same template strand resulting in DNA damage.
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DOI：
10.1038/s41467-023-44443-0
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发表时间：
2024-01-02
影响因子：
16.6
通讯作者：
Sun, Qianwen
中科院分区：
文献类型：
--
作者：
Zhang, Weifeng;Yang, Zhuo;Wang, Wenjie;Sun, Qianwen
转录复制冲突（TRC），尤其是头向 TRC（HO-TRC）可以引入 R 环和 DNA 损伤，然而，其潜在机制仍不清楚。我们之前发现了一种叶绿体定位的 RNase H1 蛋白 AtRNH1C，它可以去除 R 环并放松 HO-TRC 以保证基因组完整性。通过诱变筛选，我们发现叶绿体定位的引物酶 ATH 中存在突变，该突变削弱了 DNA 模板的结合亲和力并降低了 RNA 引物合成和递送的活性。这减慢了 DNA 复制，并减少了转录复制的竞争，从而挽救了 atrnh1c 的发育缺陷。链特异性 DNA 损伤测序表明，HO-TRC 在滞后链转录单元末端造成 DNA 损伤，而 ATH 的过度表达可以增强 HO-TRC 并加剧 DNA 损伤。此外，质体DNA聚合酶Pol1A的突变同样可以挽救atrnh1c突变体的缺陷。综上所述，这些结果说明了生物体之间潜在的保守机制，其中引物酶活性可以促进转录-复制冲突的发生，从而导致 HO-TRC 和基因组不稳定。解决由转录复制冲突 (TRC) 引起的 R 环对于生物体基因组稳定性至关重要。在这里，作者表明，叶绿体定位的引物酶 ATH 加剧了模板链竞争，并加剧了 Head-On TRC 诱导的 DNA 损伤。
Transcription-replication conflicts (TRCs), especially Head-On TRCs (HO-TRCs) can introduce R-loops and DNA damage, however, the underlying mechanisms are still largely unclear. We previously identified a chloroplast-localized RNase H1 protein AtRNH1C that can remove R-loops and relax HO-TRCs for genome integrity. Through the mutagenesis screen, we identify a mutation in chloroplast-localized primase ATH that weakens the binding affinity of DNA template and reduces the activities of RNA primer synthesis and delivery. This slows down DNA replication, and reduces competition of transcription-replication, thus rescuing the developmental defects of atrnh1c. Strand-specific DNA damage sequencing reveals that HO-TRCs cause DNA damage at the end of the transcription unit in the lagging strand and overexpression of ATH can boost HO-TRCs and exacerbates DNA damage. Furthermore, mutation of plastid DNA polymerase Pol1A can similarly rescue the defects in atrnh1c mutants. Taken together these results illustrate a potentially conserved mechanism among organisms, of which the primase activity can promote the occurrence of transcription-replication conflicts leading to HO-TRCs and genome instability. Resolving R-loops caused by transcription-replication conflicts (TRCs) is vital to genome stability in organisms. Here, the authors show that the chloroplast-localized primase ATH intensifies template strand competition and exacerbates the Head-On TRCs induced DNA damage.
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影响因子：
64.5
作者：
Haradhvala NJ;Polak P;Stojanov P;Covington KR;Shinbrot E;Hess JM;Rheinbay E;Kim J;Maruvka YE;Braunstein LZ;Kamburov A;Hanawalt PC;Wheeler DA;Koren A;Lawrence MS;Getz G
通讯作者：
Getz G
影响因子：
64.8
作者：
Lee, JB;Hite, RK;van Oijen, AM
通讯作者：
van Oijen, AM
转录复制冲突取向调节R环水平并激活不同的DNA损伤反应。
影响因子：
64.5
作者：
Hamperl S;Bocek MJ;Saldivar JC;Swigut T;Cimprich KA
通讯作者：
Cimprich KA
影响因子：
16
作者：
Brickner, Joshua R.;Garzon, Jada L.;Cimprich, Karlene A.
通讯作者：
Cimprich, Karlene A.
影响因子：
5.6
作者：
KITANI, T;YODA, KY;OKAZAKI, T
通讯作者：
OKAZAKI, T