Bélanger C, MacKenzie R E
Department of Biochemistry, McGill University, Montreal, Quebec.
Gene. 1991 Jan 15;97(2):283-8. doi: 10.1016/0378-1119(91)90064-i.
The structural organization of the entire nuclear gene (NMDMC) encoding the mitochondrial (mt) NAD-dependent methylenetetrahydrofolate dehydrogenase-methenyltetrahydrofolate cyclohydrolase enzyme (NMDMC) was determined by analysis of clones obtained from a lambda EMBL3 murine genomic DNA library. The gene is approx. 13 kb in length and contains eight exons and seven introns. All exon/intron splice junctions follow the GT/AG rule. The amino acid presequence, which is essential for transport of the NMDMC enzyme precursor into mt, is encoded almost entirely in the first exon. Two major transcriptional start points (tsp), located 33 and 75 nucleotides upstream from the AUG start codon, were revealed by S1 nuclease mapping and RNase protection analyses. The immediate 5'-flanking region of the first exon contains one CAAT box, a TATA-like box and three sites homologous to the consensus sequence for the binding of transcription factor Sp1.
通过对从λEMBL3小鼠基因组DNA文库中获得的克隆进行分析，确定了编码线粒体（mt）NAD依赖性亚甲基四氢叶酸脱氢酶-亚甲基四氢叶酸环水解酶（NMDMC）的整个核基因（NMDMC）的结构组织。该基因长度约为13 kb，包含8个外显子和7个内含子。所有外显子/内含子剪接连接均遵循GT/AG规则。对于NMDMC酶前体转运到线粒体中必不可少的氨基酸前序列几乎完全由第一个外显子编码。通过S1核酸酶图谱分析和RNA酶保护分析揭示了两个主要转录起始点（tsp），分别位于AUG起始密码子上游33和75个核苷酸处。第一个外显子紧邻的5'侧翼区域包含一个CAAT盒、一个类TATA盒以及三个与转录因子Sp1结合的共有序列同源的位点。
