Faithful cell-cycle regulation of a recombinant mouse histone H4 gene is controlled by sequences in the 3'-terminal part of the gene.
Faithful cell-cycle regulation of a recombinant mouse histone H4 gene is controlled by sequences in the 3'-terminal part of the gene.
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重组小鼠组蛋白 H4 基因的忠实细胞周期调控由该基因 3 末端部分的序列控制。
DOI：
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发表时间：
1985
影响因子：
11.1
通讯作者：
D. Schümperli
中科院分区：
文献类型：
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作者：
B. Lüscher;C. Stauber;R. Schindler;D. Schümperli
我们分析了 21-Tb 细胞（一种小鼠肥大细胞瘤细胞周期突变体）中内源组蛋白 H4 基因和新引入的 H4 基因的表达。 G1 期停滞细胞中的内源 H4 mRNA 丰度比指数增殖细胞低 120-180 倍。然而，根据新生转录本的体外延伸确定，在这些条件下，H4 转录率仅降低了 3 倍。这表明组蛋白 mRNA 水平的转录后控制很重要，与已发表的数据一致。我们通过 DNA 介导的基因转移将小鼠 H4 基因引入 21-Tb 细胞中，该基因通过在其编码序列中插入 12 个碱基对 (bp) 进行修饰。该基因的转录物水平与内源基因的转录物水平同时受到调节。此外，猿猴病毒40（SV40）早期启动子与含有小鼠H4基因3'端一半的463bp片段（包括230bp间隔序列）融合，导致SV40/H4融合RNA的表达受到调节。然而，一小部分 SV40 起始转录物并未加工至组蛋白特异性 3' 末端，而是通过下游大肠杆菌半乳糖激酶基因进一步延伸至 SV40 聚腺苷酸化位点。与短 SV40/H4 RNA 相比，这些较长转录物的水平在 G1 期停滞的细胞中并未降低。这些结果表明，H4 基因 3' 末端部分的序列可以调节细胞周期中的基因表达，大概是在转录后水平，只要它们的位置不比正常情况距离末端远得多。
We have analyzed the expression of endogenous histone H4 genes and of a newly introduced H4 gene in 21-Tb cells, a mouse mastocytoma cell-cycle mutant. Endogenous H4 mRNAs were less abundant by a factor of 120-180 in G1-arrested than in exponentially multiplying cells. However, H4 transcription rates were only decreased by a factor of 3 under these conditions, as determined by in vitro elongation of nascent transcripts. This indicates that post-transcriptional control of histone mRNA levels is important, in accord with published data. We introduced a mouse H4 gene, modified by a 12-base-pair (bp) insertion in its coding sequence, into 21-Tb cells by DNA-mediated gene transfer. The levels of transcripts from this gene were regulated in parallel with those of the endogenous genes. Moreover, fusion of the simian virus 40 (SV40) early promoter to a 463-bp fragment containing the 3'-terminal half of the mouse H4 gene, including 230 bp of spacer sequences, led to the regulated expression of SV40/H4 fusion RNA. However, a small proportion of SV40-initiated transcripts were not processed to histone-specific 3' ends, but extended farther through the downstream Escherichia coli galactokinase gene to a SV40 polyadenylylation site. In contrast to the short SV40/H4 RNA, the levels of these longer transcripts were not reduced in G1-arrested cells. These results show that sequences in the 3'-terminal part of the H4 gene can regulate gene expression in the cell cycle, presumably at the post-transcriptional level, as long as they are not positioned much more distant from the terminus than normal.