DENOVO METHYLATION, EXPRESSION, AND INFECTIVITY OF RETROVIRAL GENOMES INTRODUCED INTO EMBRYONAL CARCINOMA-CELLS
DENOVO METHYLATION, EXPRESSION, AND INFECTIVITY OF RETROVIRAL GENOMES INTRODUCED INTO EMBRYONAL CARCINOMA-CELLS
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DOI：
10.1073/pnas.79.13.4098
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发表时间：
1982-01-01
期刊：
影响因子：
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通讯作者：
JAENISCH, R
中科院分区：
文献类型：
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作者：
STEWART, CL;STUHLMANN, H;JAENISCH, R
在小鼠胚胎癌（EC）细胞中研究了Moloney小鼠白血病病毒表达的阻断。感染的EC细胞含有多达100个整合的前病毒基因组。通过XC空斑和病毒特异性RNA合成测量的病毒表达没有发生在显著水平，与生产性感染的分化细胞相反。对感染的EC细胞中DNA的分析显示，前病毒基因组高度甲基化，如它们对Sma I切割的抗性所示。在感染的分化细胞中整合的前病毒基因组很容易被Sma I切割，因此在这些位点没有甲基化。将感染的EC细胞的DNA转染到允许病毒表达的细胞中不能诱导病毒表达。前病毒基因组具有潜在的感染性，因为当用5-氮杂胞苷处理用于转染的受体细胞时，它们诱导XC斑块。这种药物被认为会干扰DNA甲基化。导入EC细胞的前病毒基因组的表达明显受到抑制，这种失活似乎与病毒DNA的从头甲基化相关。因此，从头甲基化活性可能是早期胚胎细胞的特征。
The block to expression of Moloney murine leukemia virus was investigated in murine embryonal carcinoma (EC) cells. Infected EC cells contained up to 100 integrated proviral genomes. Expression of virus as measured by XC plaque and virus-specific RNA synthesis did not occur at significant levels, in contrast to productively infected differentiated cells. Analysis of the DNA in the infected EC cells revealed that the proviral genomes were highly methylated, as shown by their resistance to cleavage by Sma I. Integrated proviral genomes in infected differentiated cells were readily cut by Sma I and thus were not methylated at these sites. Transfection of DNA from infected EC cells to cells permissive for virus expression failed to induce virus expression. The proviral genomes were potentially infectious because they induced XC plaques when the recipient cells for transfection were treated with 5-azacytidine. This drug is believed to interfere with DNA methylation. Expression of proviral genomes introduced into EC cells apparently is suppressed and this inactivation appears to be correlated with the de novo methylation of the viral DNA. De novo methylation activity thus may be a characteristic of early embryonic cells.