Replication initiation from a novel origin identified in the Th2 cytokine cluster locus requires a distant conserved noncoding sequence
Replication initiation from a novel origin identified in the Th2 cytokine cluster locus requires a distant conserved noncoding sequence
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DOI：
10.4049/jimmunol.176.9.5446
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发表时间：
2006-05-01
影响因子：
4.4
通讯作者：
Miyatake, Shoichiro
中科院分区：
文献类型：
--
作者：
Hayashida, Toshiro;Oda, Masako;Miyatake, Shoichiro
Th 细胞的谱系定型与细胞因子特定转录程序的建立有关。然而，Th 细胞分化如何影响 DNA 复制程序尚未得到解决。为了深入了解分化诱导的转录调控和 DNA 复制起始之间的相互作用，我们利用了幼稚 T 细胞的体外分化系统，在该系统中，人们可以操纵它们分化为 Th1 或 Th2 细胞。我们在小鼠 IL-4/IL-13 基因座中寻找复制起点，并比较了它们在体外衍生自相同前体 T 细胞的两个 Th 细胞谱系中的概况。我们鉴定了 IL-13 外显子 4 下游的复制起点 (ori(IL-13))，并表明该起点在 Th2 和 Th1 细胞中均起作用。 IL-41/IL-13 基因间区域中的一个名为 CNS-1（保守非编码序列 1）的远距离调节元件与 Th2 特异性 DNase I 超敏位点一致，并且是 Th2 细胞因子高效、协调表达所必需的。 CNS-1 缺陷小鼠的 Th1 和 Th2 细胞中 ori(IL-13) 的复制起始显着减少。然而，在野生型或 CNS-1 缺失背景下，Th1 和 Th2 细胞中该位点的复制时间始终处于 S 期早期。因此，基因间区域中的保守非编码元件以独立于其对谱系特异性转录的影响的方式调节从远处复制起点的复制起始，但不依赖于该起点周围片段的复制时间。
Lineage commitment of Th cells is associated with the establishment of specific transcriptional programs of cytokines. However, how Th cell differentiation affects the program of DNA replication has not been addressed. To gain insight into interplays between differentiation-induced transcription regulation and initiation of DNA replication, we took advantage of an in vitro differentiation system of naive T cells, in which one can manipulate their differentiation into Th1 or Th2 cells. We searched for replication origins in the murine IL-4/IL-13 locus and compared their profiles in the two Th cell lineages which were derived in vitro from the same precursor T cells. We identified a replication origin (ori(IL-13)) downstream from exon 4 of IL-13 and showed that this origin functions in both Th2 and Th1 cells. A distant regulatory element called CNS-1 (conserved noncoding sequence 1) in the IL-41/IL-13 intergenic region coincides with a Th2-specific DNase I-hypersensitive site and is required for efficient, coordinated expression of Th2 cytokines. Replication initiation from ori(IL-13) is significantly reduced in Th1 and Th2 cells derived from CNS-1-deficient mice. However, the replication timing of this locus is consistently early during S phase in both Th1 and Th2 cells under either the wild-type or CNS-1 deletion background. Thus, the conserved noncoding element in the intergenic region regulates replication initiation from a distant replication origin in a manner independent from its effect on lineage-specific transcription but not the replication timing of the segment surrounding this origin.