Toki T, Itoh J, Kitazawa J, Arai K, Hatakeyama K, Akasaka J, Igarashi K, Nomura N, Yokoyama M, Yamamoto M, Ito E
Department of Pediatrics, Hirosaki University, Japan.
Oncogene. 1997 Apr 24;14(16):1901-10. doi: 10.1038/sj.onc.1201024.
The transcription factor NF-E2, a heterodimeric protein complex composed of p45 and small Maf family proteins, is considered crucial for the regulation of erythroid gene expression and platelet formation. To facilitate the characterization of NF-E2 functions in human cells, we isolated cDNAs encoding two members of the small Maf family, MafK and MafG. The human mafK and mafG genes encode proteins of 156 and 162 amino acid residues, respectively, whose deduced amino acid sequences show approximately 95% identity to their respective chicken counterparts. Expression of mafK mRNA is high in heart, skeletal muscle and placenta, whereas mafG mRNA is abundant in skeletal muscle and is moderately expressed in heart and brain. Both are expressed in all hematopoietic cell lines, including those of erythroid and megakaryocytic lineages. In electrophoretic gel mobility shift assays binding to NF-E2 sites was found to depend on formation of homodimers or heterodimers with p45 and p45-related CNC family proteins. The results suggest that the small Maf family proteins function in human cells through interaction with various basic-leucine zipper-type transcription factors.
转录因子NF-E2是一种由p45和小Maf家族蛋白组成的异二聚体蛋白复合物，被认为对红系基因表达的调控和血小板形成至关重要。为了便于在人类细胞中表征NF-E2的功能，我们分离了编码小Maf家族两个成员MafK和MafG的cDNA。人类mafK和mafG基因分别编码156和162个氨基酸残基的蛋白质，其推导的氨基酸序列与其各自的鸡对应物显示出约95%的同一性。mafK mRNA在心脏、骨骼肌和胎盘中表达较高，而mafG mRNA在骨骼肌中丰富，在心脏和大脑中中等表达。两者在所有造血细胞系中均有表达，包括红系和巨核细胞系的细胞系。在电泳凝胶迁移率变动分析中，发现与NF-E2位点的结合取决于与p45和p45相关的CNC家族蛋白形成同二聚体或异二聚体。结果表明，小Maf家族蛋白通过与各种碱性亮氨酸拉链型转录因子相互作用在人类细胞中发挥功能。
