Inhibition of T-cell proliferation by a MYB antisense oligomer is accompanied by selective down-regulation of DNA polymerase alpha expression.
Inhibition of T-cell proliferation by a MYB antisense oligomer is accompanied by selective down-regulation of DNA polymerase alpha expression.
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MYB 反义寡聚物对 T 细胞增殖的抑制伴随着 DNA 聚合酶 α 表达的选择性下调。
DOI：
10.1073/pnas.87.15.5963
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发表时间：
1990
影响因子：
11.1
通讯作者：
Calabretta,B
中科院分区：
文献类型：
--
作者：
Venturelli,D;Travali,S;Calabretta,B
我们最近发现，在人外周血单个核细胞（PBMC）暴露于人c-myb（指定MYB）反义寡脱氧核苷酸抑制MYB蛋白的合成，防止进入S期和细胞增殖。为了确定人类c-myb蛋白（MYB）合成下调干扰DNA合成的机制，我们分析了正常和白血病T淋巴细胞暴露于MYB反义寡核苷酸后DNA聚合酶α和增殖细胞核抗原（PCNA）的mRNA水平，这两种基因是DNA合成所需的转录本。DNA聚合酶α的表达被抑制在正常T淋巴细胞从G 0期到S期的进展，并在指数增长的CCRF-CEM白血病细胞，而PCNA的表达被抑制，只有在有丝分裂原刺激的PBMC和保持基本上不受影响的白血病T细胞系。通过分析温度敏感性（ts）成纤维细胞系（TK-ts 13; TK是胸苷激酶）中的DNA聚合酶α mRNA水平，进一步证明了MYB和DNA聚合酶α mRNA表达之间的功能联系，该细胞系组成型表达由猿猴病毒40（SV 40）启动子驱动的人MYB mRNA。在表达MYB的TK-ts 13细胞中，DNA聚合酶α mRNA水平在转移到非允许温度39.6摄氏度后不受影响，而在亲本细胞系中，DNA聚合酶α mRNA水平很容易下调。这些发现表明，MYB的表达与高水平表达MYB的细胞中的DNA聚合酶α的表达相关，并表明在正常T淋巴细胞的细胞周期进程中，c-myb和DNA聚合酶α mRNA表达之间存在功能性联系。
We recently found that inhibition of MYB protein synthesis in human peripheral blood mononuclear cells (PBMC) exposed to human c-myb (designated MYB) antisense oligodeoxynucleotides prevents entry into S phase and cell proliferation. To determine the mechanism(s) by which down-regulation of human c-myb protein (MYB) synthesis interferes with DNA synthesis, we analyzed mRNA levels of DNA polymerase alpha and proliferating cell nuclear antigen (PCNA), transcripts of two genes required for DNA synthesis, in normal and leukemic T lymphocytes exposed to MYB antisense oligodeoxynucleotides. Expression of DNA polymerase alpha was inhibited both in normal T lymphocytes progressing from G0 to S phase and in exponentially growing CCRF-CEM leukemic cells, whereas expression of PCNA was inhibited only in mitogen-stimulated PBMC and remained essentially unaffected in the leukemia T-cell line. The functional link between expression of MYB and DNA polymerase alpha mRNAs was further demonstrated by analyzing DNA polymerase alpha mRNA levels in a temperature-sensitive (ts) fibroblast cell line (TK-ts13; TK is thymidine kinase) constitutively expressing human MYB mRNA driven by the simian virus 40 (SV40) promoter. In the MYB-expressing TK-ts13 cells, DNA polymerase alpha mRNA levels were unaffected following shift to the nonpermissive temperature of 39.6 degrees C, whereas in the parental line, DNA polymerase alpha mRNA levels were readily down-regulated. These findings indicate that the expression of MYB is related to that of DNA polymerase alpha in cells expressing MYB at high levels and suggest that there is a functional link between c-myb and DNA polymerase alpha mRNA expression during cell cycle progression of normal T lymphocytes.