R 环是三聚体核酸结构，当 RNA 分子与其互补的 DNA 链杂交并取代相反的链时形成。这些结构调节转录和复制，但可能会形成异常的 R 环，如果不解决，就会导致 DNA 断裂和基因组不稳定。在许多癌症以及维持高风险人乳头瘤病毒的细胞中，R 环水平升高。我们研究了正常角质形成细胞和源自宫颈癌前病变 (CIN I) 的 HPV 阳性细胞之间 R 环的分布和功能如何变化。研究发现，HPV 阳性细胞中与细胞基因相关的 R 环水平比正常角质形成细胞高出 10 倍，而 ALU1 元件的水平则增加了 500 倍。增强的 R 环的存在导致基因转录水平发生改变，数量增加与减少的数量相同。虽然没有检测到由于 R 环水平增强而对转录产生统一的整体影响，但仅在 HPV 阳性细胞中，几个途径中的基因表达协调增加或减少。这包括先天免疫通路中基因的下调，例如 DDX58、IL-6、STAT1、IFN-β 和 NLRP3。所有依赖于 R 环的差异表达先天免疫基因也与 H3K36me3 修饰组蛋白相关。 HPV 阳性细胞中因 R 环存在而上调的基因包括 DNA 损伤修复中的基因，例如 ATM、ATRX 和 Fanconi 贫血途径的成员。这些基因仅在 HPV 阳性细胞中表现出 R 环和 H3K36me3 以及 γH2AX 组蛋白标记之间的连锁。这些研究确定了 HPV 阳性细胞中 DNA 损伤修复以及 R 环和 γH2AX/H3K36me3 组蛋白标记的先天免疫调节途径之间的潜在联系，可能有助于调节 HPV 发病机制的重要功能。版权所有：© 2024 Templeton, Laimins。这是一篇根据知识共享署名许可条款分发的开放获取文章，允许在任何媒体上不受限制地使用、分发和复制，前提是注明原始作者和来源。

R-loops are trimeric nucleic acid structures that form when an RNA molecule hybridizes with its complementary DNA strand, displacing the opposite strand. These structures regulate transcription as well as replication, but aberrant R-loops can form, leading to DNA breaks and genomic instability if unresolved. R-loop levels are elevated in many cancers as well as cells that maintain high-risk human papillomaviruses. We investigated how the distribution as well as function of R-loops changed between normal keratinocytes and HPV positive cells derived from a precancerous lesion of the cervix (CIN I). The levels of R-loops associated with cellular genes were found to be up to 10-fold higher in HPV positive cells than in normal keratinocytes while increases at ALU1 elements increased by up to 500-fold. The presence of enhanced R-loops resulted in altered levels of gene transcription, with equal numbers increased as decreased. While no uniform global effects on transcription due to the enhanced levels of R-loops were detected, genes in several pathways were coordinately increased or decreased in expression only in the HPV positive cells. This included the downregulation of genes in the innate immune pathway, such as DDX58, IL-6, STAT1, IFN-β, and NLRP3. All differentially expressed innate immune genes dependent on R-loops were also associated with H3K36me3 modified histones. Genes that were upregulated by the presence of R-loops in HPV positive cells included those in the DNA damage repair such as ATM, ATRX, and members of the Fanconi Anemia pathway. These genes exhibited a linkage between R-loops and H3K36me3 as well as γH2AX histone marks only in HPV positive cells. These studies identify a potential link in HPV positive cells between DNA damage repair as well as innate immune regulatory pathways with R-loops and γH2AX/H3K36me3 histone marks that may contribute to regulating important functions for HPV pathogenesis.Copyright: © 2024 Templeton, Laimins. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.