Mao Z, Liu S, Cai J, Huang Z Z, Lu S C
Department of Medicine, University of Southern California School of Medicine, Los Angeles 90033, USA.
Biochem Biophys Res Commun. 1998 Jul 30;248(3):479-84. doi: 10.1006/bbrc.1998.8965.
Methionine adenosyltransferase (MAT) is a critical cellular enzyme which catalyzes the formation of S-adenosylmethionine, the principal methyl donor. In mammals, two different genes, MAT1A and MAT2A, encode for liver-specific and non-liver-specific MAT, respectively. We have cloned and characterized a 1.4-kb 5'-flanking region of the human MAT2A (GenBank Accession No. AF039088). Two major transcriptional start sites were identified by primer extension and S1 nuclease protection analysis; one was within 10 nucleotides downstream and the other was located at 158 nucleotides upstream from the consensus TATA box, respectively. The promoter is highly GC rich (75%) in the first 300 base pairs and contains several Sp-1 binding sites, a C/EBP, a HSF2, a STATx, a c-Myb, several v-Myb, and numerous GATA consensus binding sites. The human MAT2A promoter was able to efficiently drive luciferase expression in both Jurkat and 293 cells, but sequential deletion analysis of the promoter revealed that different regions of the promoter are important for cell-specific MAT2A expression.
甲硫氨酸腺苷转移酶（MAT）是一种关键的细胞酶，它催化主要甲基供体S-腺苷甲硫氨酸的形成。在哺乳动物中，两个不同的基因MAT1A和MAT2A分别编码肝脏特异性和非肝脏特异性的MAT。我们已经克隆并鉴定了人类MAT2A基因1.4kb的5'侧翼区域（GenBank登录号：AF039088）。通过引物延伸和S1核酸酶保护分析确定了两个主要转录起始位点；一个位于共有TATA框下游10个核苷酸内，另一个位于其上游158个核苷酸处。该启动子在前300个碱基对中富含GC（75%），并包含几个Sp-1结合位点、一个C/EBP、一个HSF2、一个STATx、一个c-Myb、几个v-Myb以及众多GATA共有结合位点。人类MAT2A启动子能够在Jurkat细胞和293细胞中有效驱动荧光素酶表达，但对该启动子进行连续缺失分析表明，启动子的不同区域对细胞特异性MAT2A表达很重要。
