Nuchprayoon I, Meyers S, Scott L M, Suzow J, Hiebert S, Friedman A D
Division of Pediatric Oncology, Johns Hopkins Oncology Center, Johns Hopkins University, Baltimore, Maryland 21287.
Mol Cell Biol. 1994 Aug;14(8):5558-68. doi: 10.1128/mcb.14.8.5558-5568.1994.
The myeloperoxidase (MPO) and neutrophil elastase genes are expressed specifically in immature myeloid cells. The integrity of a polyomavirus enhancer core sequence, 5'-AACCACA-3', is critical to the activity of the murine MPO proximal enhancer. This element binds two species, myeloid nuclear factors 1 alpha and 1 beta (MyNF1 alpha and -beta), present in 32D cl3 myeloid cell nuclear extracts. The levels of the MyNF1s increase during early 32D cl3 cell granulocytic differentiation. Both MyNF1 alpha and -beta supershift with an antiserum raised by using a peptide derived from the N terminus of polyomavirus enhancer-binding protein 2/core-binding factor (PEBP2/CBF) alpha subunit. The specific peptide inhibits these supershifts. In vitro-translated PEBP2/CBF DNA-binding domain binds the murine MPO PEBP2/CBF site. An alternate PEBP2/CBF consensus site, 5'-GACCGCA-3', but not a simian virus 40 enhancer core sequence, 5'-TTCCACA-3', binds the MyNF1s in vitro and activates a minimal murine MPO-thymidine kinase promoter in vivo. The murine neutrophil elastase gene 100-bp 5'-flanking sequences contain several functional elements, including potential binding sites for PU.1, C/EBP, c-Myb, and PEBP2/CBF. The functional element 5'-GGCCACA-3' located at positions -66 to 72 differs from the PEBP2/CBF consensus (5'-PuACCPuCA-3') only by an A-to-G transition at position 2. This DNA element binds MyNF1 alpha and -beta weakly. The N terminis of two PEBP2/CBF alpha subunit family members, PEBP2 alpha A and PEBP2 alpha B (murine AML1), are nearly identical, and 32D c13 cl3 cells contain both corresponding mRNAs. Since t(8;21), t(3;21), and inv(16), associated with myeloid leukemias, disrupt subunits of PEBP2/CBF, we speculate that the resulting oncoproteins, AML1-ETO, AML1-EAP, AML1-Evi1, and CBF beta-MYH11, inhibit early myeloid differentiation.
髓过氧化物酶（MPO）和中性粒细胞弹性蛋白酶基因在未成熟髓样细胞中特异性表达。多瘤病毒增强子核心序列5'-AACCACA-3'的完整性对于小鼠MPO近端增强子的活性至关重要。该元件结合存在于32D cl3髓样细胞核提取物中的两种蛋白，即髓核因子1α和1β（MyNF1α和-β）。在32D cl3细胞早期粒细胞分化过程中，MyNF1s的水平升高。MyNF1α和-β均与使用源自多瘤病毒增强子结合蛋白2/核心结合因子（PEBP2/CBF）α亚基N端的肽产生的抗血清发生超迁移。该特异性肽可抑制这些超迁移。体外翻译的PEBP2/CBF DNA结合结构域可结合小鼠MPO的PEBP2/CBF位点。一个替代的PEBP2/CBF共有位点5'-GACCGCA-3'，而非猴病毒40增强子核心序列5'-TTCCACA-3'，在体外结合MyNF1s并在体内激活最小的小鼠MPO-胸苷激酶启动子。小鼠中性粒细胞弹性蛋白酶基因100 bp的5'侧翼序列包含几个功能元件，包括PU.1、C/EBP、c-Myb和PEBP2/CBF的潜在结合位点。位于-66至72位的功能元件5'-GGCCACA-3'与PEBP2/CBF共有序列（5'-PuACCPuCA-3'）仅在第2位有一个A到G的转换。该DNA元件与MyNF1α和-β的结合较弱。PEBP2/CBFα亚基家族的两个成员PEBP2αA和PEBP2αB（小鼠AML1）的N端几乎相同，32D c13 cl3细胞同时含有这两种相应的mRNA。由于与髓系白血病相关的t(8;21)、t(3;21)和inv(16)会破坏PEBP2/CBF的亚基，我们推测由此产生的癌蛋白AML1-ETO、AML1-EAP、AML1-Evi1和CBFβ-MYH11会抑制早期髓样分化。
