EPIDERMAL GROWTH FACTOR-STIMULATED PARATHYROID HORMONE-RELATED PROTEIN EXPRESSION INVOLVES INCREASED GENE-TRANSCRIPTION AND MESSENGER-RNA STABILITY
EPIDERMAL GROWTH FACTOR-STIMULATED PARATHYROID HORMONE-RELATED PROTEIN EXPRESSION INVOLVES INCREASED GENE-TRANSCRIPTION AND MESSENGER-RNA STABILITY
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DOI：
10.1042/bj3070159
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发表时间：
1995-04-01
影响因子：
4.1
通讯作者：
GILLESPIE, MT
中科院分区：
文献类型：
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作者：
HEATH, JK;SOUTHBY, J;GILLESPIE, MT
表皮生长因子（EGF）对人角质形成细胞系HaCaT的甲状旁腺相关蛋白（PTHrP）基因表达产生快速而显著的影响。最大有效浓度的EGF使PTHrP mRNA和分泌PTHrP的稳态水平增加10倍，EGF同时增加PTHrP基因的转录和PTHrP mRNA的稳定性。核运行的分析表明，在EGF刺激的细胞中的转录速率增加了4倍，而瞬时转染分析表明，EGF对转录的作用涉及富含GC的启动子，P2，和下游TATA启动子，P3，但显然不是上游TATA启动子，P1。在EGF处理产生更稳定的PTHrP转录本的实验中，c-fos mRNA的半衰期没有改变，表明EGF的相对特异性作用。此外，只有那些含有两个交替3'外显子（外显子VII和VIII）的PTHrPmRNA是稳定的，那些含有外显子IX的PTHrPmRNA是不稳定的。逆转录PCR表明，EGF产生差异增加的PTHrP启动子启动的PTHrP mRNA的丰度。主要的影响是由P1和P2启动的转录本的丰度，P3启动的转录本的调节不太明显。因此，EGF对HaCaT细胞中PTHrP基因表达的调节是多因素的，其在基因5'和3'末端的作用的组合有利于含有外显子I、VII和VIII的PTHrP mRNA亚群的积累。
Epidermal growth factor (EGF) produced rapid and striking effects on parathyroid hormone-related protein (PTHrP) gene expression in the immortalized human keratinocyte cell line, HaCaT, Steady-state levels of PTHrP mRNA and secreted PTHrP were increased 10-fold by maximally effective concentrations of EGF, EGF increased both PTHrP gene transcription and PTHrP mRNA stability. Nuclear run-on assays demonstrated a 4-fold increase in transcriptional rate in EGF-stimulated cells while transient transfection analysis indicated that the action of EGF on transcription involved both the GC-rich promoter, P2, and the downstream TATA promoter, P3, but apparently not the upstream TATA promoter, P1. In experiments where EGF treatment produced more stable PTHrP transcripts, the half-life of c-fos mRNA was unaltered, suggesting a relatively specific effect of EGF. Moreover, only those species of PTHrP mRNA containing two of the alternative 3' exons (exons VII and VIII) were stable, those containing exon IX were not. Reverse-transcription PCR demonstrated that EGF produced differential increases in the abundance of PTHrP mRNA species initiated by the three PTHrP promoters. The major effect was seen on the abundance of transcripts initiated by P1 and P2, with less marked regulation of P3-initiated transcripts, Thus EGF regulation of PTHrP gene expression in HaCaT cells is multifactorial and the combination of its actions at the 5' and 3' ends of the gene favours the accumulation of subpopulations of PTHrP mRNA containing exons I, VII and VIII.