Orii K E, Orii K O, Souri M, Orii T, Kondo N, Hashimoto T, Aoyama T
Department of Pediatrics, Gifu University School of Medicine, Gifu 500-8076, Japan.
J Biol Chem. 1999 Mar 19;274(12):8077-84. doi: 10.1074/jbc.274.12.8077.
Human HADHA and HADHB genes encode the subunits of an enzyme complex, the trifunctional protein, involved in mitochondrial beta-oxidation of fatty acids. Both genes are located in the same region of chromosome 2p23. We isolated genomic clones, including 5' flanking regions, for HADHA and HADHB. Sequencing revealed that both of these genes are linked in a head-to-head arrangement on opposite strands and have in common a 350-bp 5' flanking region. The 5' flanking region has bidirectional promoter activity within this region; two cis elements proved critical for the activity. Transcription factor Sp1 functions as an activator for the bidirectional promoter by binding to both elements. Therefore, expression of trifunctional protein subunits are probably coordinately regulated by a common promoter and by Sp1.
人类HADHA和HADHB基因编码一种酶复合物的亚基，即参与脂肪酸线粒体β氧化的三功能蛋白。这两个基因都位于2号染色体p23区域的同一位置。我们分离出了包含HADHA和HADHB基因5'侧翼区域的基因组克隆。测序结果显示，这两个基因以头对头的方式位于相反的链上，并且共有一个350bp的5'侧翼区域。该5'侧翼区域在这一区域内具有双向启动子活性；有两个顺式元件对该活性至关重要。转录因子Sp1通过与这两个元件结合，作为双向启动子的激活剂发挥作用。因此，三功能蛋白亚基的表达可能由一个共同的启动子和Sp1协同调节。
