PDF(Pubmed)
Abstract：
During HTLV-1 infection, the virus integrates into the host cell genome as a provirus with a single CCCTC binding protein (CTCF) binding site (vCTCF-BS), which acts as an insulator between transcriptionally active and inactive regions. Previous studies have shown that the vCTCF-BS is important for maintenance of chromatin structure, regulation of viral expression, and DNA and histone methylation. Here, we show that the vCTCF-BS also regulates viral infection and pathogenesis in vivo in a humanized (Hu) mouse model of adult T-cell leukemia/lymphoma. Three cell lines were used to initiate infection of the Hu-mice, i) HTLV-1-WT which carries an intact HTLV-1 provirus genome, ii) HTLV-1-CTCF, which contains a provirus with a mutated vCTCF-BS which abolishes CTCF binding, and a stop codon immediate upstream of the mutated vCTCF-BS which deletes the last 23 amino acids of p12, and iii) HTLV-1-p12stop that contains the intact vCTCF-BS, but retains the same stop codon in p12 as in the HTLV-1-CTCF cell line. Hu-mice were infected with mitomycin treated or irradiated HTLV-1 producing cell lines. There was a delay in pathogenicity when Hu-mice were infected with the CTCF virus compared to mice infected with either p12 stop or WT virus. Proviral load (PVL), spleen weights, and CD4 T cell counts were significantly lower in HTLV-1-CTCF infected mice compared to HTLV-1-p12stop infected mice. Furthermore, we found a direct correlation between the PVL in peripheral blood and death of HTLV-1-CTCF infected mice. In cell lines, we found that the vCTCF-BS regulates Tax expression in a time-dependent manner. The scRNAseq analysis of splenocytes from infected mice suggests that the vCTCF-BS plays an important role in activation and expansion of T lymphocytes in vivo. Overall, these findings indicate that the vCTCF-BS regulates Tax expression, proviral load, and HTLV pathogenicity in vivo.
摘要：
在HTLV-1感染期间，该病毒以单一CCCTC结合蛋白（CTCF）结合位点（vCTCF-BS）的前病毒形式整合到宿主细胞基因组中，它充当转录活跃区和非活跃区之间的绝缘体。以前的研究表明，vCTCF-BS对维持染色质结构很重要，病毒表达的调节，DNA和组蛋白甲基化。这里,我们表明，vCTCF-BS还在成年T细胞白血病/淋巴瘤的人源化（Hu）小鼠模型中调节病毒感染和体内发病机制。使用三种细胞系来启动Hu小鼠的感染，i)携带完整HTLV-1前病毒基因组的HTLV-1-WT，ii)HTLV-1-CTCF,其中包含具有突变的vCTCF-BS的前病毒，其消除了CTCF结合，和突变vCTCF-BS上游的终止密码子，其删除p12的最后23个氨基酸，以及iii）包含完整vCTCF-BS的HTLV-1-p12stop，但在p12中保留与HTLV-1-CTCF细胞系相同的终止密码子。用丝裂霉素处理或辐照的产生HTLV-1的细胞系感染Hu-小鼠。与感染p12终止或WT病毒的小鼠相比，当Hu小鼠感染CTCF病毒时，致病性有延迟。前病毒载量（PVL），脾脏重量,与HTLV-1-p12stop感染的小鼠相比，HTLV-1-CTCF感染的小鼠中的CD4T细胞计数显着降低。此外，我们发现外周血PVL与HTLV-1-CTCF感染小鼠死亡之间存在直接相关性.在细胞系中,我们发现vCTCF-BS以时间依赖的方式调节税收表达。来自感染小鼠的脾细胞的scRNAseq分析表明，vCTCF-BS在体内T淋巴细胞的激活和扩增中起重要作用。总的来说,这些发现表明，vCTCF-BS规范税收表达，原载荷,和体内HTLV致病性。
■人类T细胞白血病病毒1型（HTLV-1）是白血病和淋巴瘤的病因，和几种炎症性医学疾病。病毒整合到宿主细胞的DNA中,并且它包括称为CTCF的细胞蛋白的单个结合位点。这种蛋白质在许多病毒的调节中很重要，以及正常和恶性细胞的特性。为了确定CTCF在体内HTLV-1发病机制中的作用，我们分析了人源化小鼠中缺乏结合位点的突变病毒。我们发现这种突变减缓了病毒传播并减轻了疾病的发展。基因表达研究表明CTCF在调节病毒基因表达和T淋巴细胞活化中的动态作用。
■人类T细胞白血病病毒1型（HTLV-1）是白血病和淋巴瘤的病因，和几种炎症性医学疾病。病毒整合到宿主细胞的DNA中,并且它包括称为CTCF的细胞蛋白的单个结合位点。这种蛋白质在许多病毒的调节中很重要，以及正常和恶性细胞的特性。为了确定CTCF在体内HTLV-1发病机制中的作用，我们分析了人源化小鼠中缺乏结合位点的突变病毒。我们发现这种突变减缓了病毒传播并减轻了疾病的发展。基因表达研究表明CTCF在调节病毒基因表达和T淋巴细胞活化中的动态作用。
