Buisson M, Manet E, Trescol-Biemont M C, Gruffat H, Durand B, Sergeant A
Ecole Normale Supérieure de Lyon-Centre National de la Recherche Scientifique UMR49, Ecole Normale Supérieure de Lyon, France.
J Virol. 1989 Dec;63(12):5276-84. doi: 10.1128/JVI.63.12.5276-5284.1989.
From the cloning and characterization of cDNAs, we found that the Epstein-Barr virus (EBV) open reading frame (ORF) BMLF1-BSLF2 coding for the early protein EB2 is present in several mRNAs generated by alternative splicing and expressed in the leftward direction from two promoters PM and PM1. The PM promoter controls the expression of two abundant mRNA species of 1.9 and 2 kilobases (kb), whereas the PM1 promoter controls the expression of at least three mRNAs 3.6, 4.0, and 4.4 kb long. The PM promoter probably overlaps with the PS promoter which controls the transcription of a 3.6-kb mRNA expressed in the rightward direction and containing the ORF BSRF1. Although it increases the amount of chloramphenicol acetyltransferase enzyme expressed from the chimeric pMCAT gene, EB2 is not a promiscuous trans-activator of gene expression and does not positively regulate its own expression from promoter PM. The EB2 activation is not promoter dependent but could possibly act by stabilizing mRNAs and increasing their translation. The PM promoter is, however, activated by the two EBV transcription trans-acting factors, EB1 and R, encoded by the EBV ORFs BZLF1 and BRLF1, respectively. EB1 activates the PM promoter from a consensus AP-1 binding site, and R activates the PM promoter from an enhancer.
通过对cDNA的克隆和特性分析，我们发现编码早期蛋白EB2的爱泼斯坦-巴尔病毒（EBV）开放阅读框（ORF）BMLF1 - BSLF2存在于通过可变剪接产生的几种mRNA中，并从两个启动子PM和PM1向左表达。PM启动子控制1.9和2千碱基（kb）的两种丰富mRNA种类的表达，而PM1启动子控制至少三种长度分别为3.6、4.0和4.4 kb的mRNA的表达。PM启动子可能与PS启动子重叠，PS启动子控制以向右方向表达且包含ORF BSRF1的3.6 kb mRNA的转录。尽管EB2增加了从嵌合pMCAT基因表达的氯霉素乙酰转移酶的量，但它不是基因表达的杂乱反式激活因子，也不会从启动子PM正向调节其自身表达。EB2的激活不依赖于启动子，但可能通过稳定mRNA并增加其翻译起作用。然而，PM启动子被分别由EBV ORFs BZLF1和BRLF1编码的两种EBV转录反式作用因子EB1和R激活。EB1从共有AP - 1结合位点激活PM启动子，而R从增强子激活PM启动子。
