A conserved region in intron 1 negatively regulates the expression of the PCNA gene.
A conserved region in intron 1 negatively regulates the expression of the PCNA gene.
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内含子 1 中的保守区域负向调节 PCNA 基因的表达。
DOI：
10.1093/nar/20.7.1769
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发表时间：
1992
影响因子：
14.9
通讯作者：
Baserga,R
中科院分区：
文献类型：
--
作者：
Alder,H;Yoshinouchi,M;Prystowsky,MB;Appasamy,P;Baserga,R
增殖细胞核抗原（PCNA）基因是一种生长调节基因，其表达受转录和转录后机制的双重调控。在以前的工作中，它表明，73 bp的CAP位点和内含子4的上游直接是主要的调控元件。我们发现内含子1也在决定PCNA mRNA水平中起作用。具体而言，我们显示：1）内含子1的缺失增加了无血清细胞中PCNA mRNA的表达; 2）内含子1中的35 bp序列，其含有特异性结合来自核提取物的蛋白质的反向CCAAT元件; 3）该内含子1序列在瞬时表达测定中抑制共转染的人PCNA基因的表达，表明其竞争阳性转录因子; 4）35 bp内含子1探针的CCAAT区域中的突变消除了其蛋白结合能力和其抑制共转染的wt PCNA基因表达的能力;和5）人内含子1的CCAAT区域在小鼠基因中高度保守。我们得出结论，内含子1的反向CCAAT区域是PCNA基因表达的负调控元件，并假设当某些蛋白质与其结合时，其抑制作用被取消，如果这些蛋白质被同源序列竞争出来，则抑制作用恢复。
The Proliferating Cell Nuclear Antigen (PCNA) gene is a growth-regulated gene, whose expression is under the control of both transcriptlonal and post-transcriptional mechanisms. In previous work, it was shown that the 73 bp immediately upstream of the CAP site and intron 4 are major regulatory elements. We show here that intron 1 also plays a role in determining the levels of PCNA mRNA. Specifically, we show: 1) deletion of intron 1 increases the expression of PCNA mRNA in serum-deprived cells; 2) a 35 bp sequence in intron 1, containing a reverse CCAAT element specifically binds proteins from nuclear extracts; 3) this intron 1 sequence inhibits the expression of a co-tranfected human PCNA gene in transient expression assays suggesting that it competes for positive transcription factors; 4) mutations in the CCAAT region of the 35bp intron 1 probe abrogate both its protein-binding capacity and its ability to inhibit the expression of a co-transfected wt PCNA gene; and 5) the CCAAT region of human intron 1 is highly conserved in the mouse gene. We conclude that the reverse CCAAT region of intron 1 is a negative regulatory element of PCNA gene expression, and hypothesize that its inhibitory effect is abolished when certain protein(s) bind to it and that inhibition is restored if these proteins are competed out by an homologous sequence.