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Cell Genetic and Molecular Analysis of the Rearranged c-myc in Mouse Plasmacytoms

小鼠浆细胞瘤中重排 c-myc 的细胞遗传学和分子分析

基本信息

批准号：
01570183
负责人：
OIKAWA Tsuneyuki
金额：
$ 1.34万
依托单位：
Hokkaido University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1989
资助国家：
日本
起止时间：
1989 至 1990
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-01570183/
关键词：
Mouse plasmacytoma Rearranged c-myc Tissue-specificity Hybrid cells DNase I sensitivity DNase I感受性がん c-myc 遺伝子発現

项目摘要

We have reported that high expression of the rearranged c-myc in mouse plasmacytoma cells is suppressed after cell fusion with fibroblastic cells. In this study, we analyzed molecular mechanism of this suppression. The suppression of the rearranged c-myc expression was also found in hybrids between plasmacytoma and T-cell lymphoma or teratocarcinoma. No involvement of DNA methylation of the rearranged c-myc in the suppression was suggested by comparing the methylation patterns in the parental and hybrid cells. Expression of the non-rearranged c-myc was enhanced by treatment of the hybrid cells with cycloheximide, while that of the rearranged c-myc was still undetectable. Run-on assay demonstrated that suppression of the rearranged c-myc expression of the rearranged c-myc expression was at transcriptional level, which was parallel to DNase I sensitivity of the gene ; higher DNase I sensitivity of the rearranged c-myc in plasmacytoma was reduced after cell fusion with fibroblastic cells. We attempted to transfer nuclear proteins from fibroblasts into plasmacytoma cells by using the rbc-ghost method, but we failed to suppress the rearranged c-myc by this method. Recently it has been reported that there is a B-cell specific enhancer containing octamer motif in 3' end of the immunoglobulin C gene. Expression of B-cell-specific Oct-2 gene is responsible for suppression of the rearranged c-myc in hybrids between plasmacytoma and non-B cells.

我们已经报道了小鼠浆细胞瘤细胞与成纤维细胞融合后，重排的c-myc的高表达被抑制。在本研究中，我们分析了这种抑制的分子机制。在浆细胞瘤与T细胞淋巴瘤或畸胎瘤的杂交瘤中也发现重排的c-myc表达被抑制。通过比较亲本细胞和杂交细胞中的甲基化模式，表明重排的c-myc的DNA甲基化不参与抑制。放线菌酮处理的杂交细胞的非重排的c-myc的表达增强，而重排的c-myc的仍然检测不到。Run-on分析表明重排c-myc基因的表达在转录水平上受到抑制，这与该基因对DNase I的敏感性相平行;浆细胞瘤中重排c-myc基因与成纤维细胞融合后对DNase I的敏感性降低。我们试图通过使用rbc-ghost方法将核蛋白从成纤维细胞转移到浆细胞瘤细胞中，但我们未能通过这种方法抑制重排的c-myc。最近有报道在免疫球蛋白C基因的3'端存在一个含有八聚体基序的B细胞特异性增强子。在浆细胞瘤和非B细胞之间的杂种中，B细胞特异性Oct-2基因的表达负责抑制重排的c-myc。