Cho Young Sun, Lee Sang Yoon, Bang In Chul, Kim Dong Soo, Nam Yoon Kwon
Department of Aquaculture, Pukyong National University, Busan 608-737, South Korea.
Fish Shellfish Immunol. 2009 Oct;27(4):571-6. doi: 10.1016/j.fsi.2009.07.003. Epub 2009 Jul 17.
The genomic structure of manganese superoxide dismutase (Mn-SOD) was characterized in Hemibarbus mylodon (Teleostei, Cypriniformes), an endangered freshwater fish species, and changes in Mn-SOD mRNA expression in response to various stimuli, such as challenge with lipopolysaccharide (LPS), bacteria, or heavy metals, were examined. H. mylodon Mn-SOD possesses well-conserved features of vertebrate Mn-SODs, including its homologous quinquepartite gene structure (five exons interrupted by four introns) and high sequence identity with vertebrate orthologs in coding regions, including a typical eukaryotic Mn-SOD signature. The 5'-regulatory upstream region of the H. mylodon Mn-SOD gene lacked a canonical TATA sequence; however, it displayed various transcription factor binding elements that may be involved in immune and stress responses, as well as the modulation of enzymes that mediate the metabolism of metals and other xenobiotics. Bioinformatic analysis of Mn-SOD genes from fish and mammalian genome databases revealed chromosomal synteny of the Mn-SOD locus in the vertebrate lineage. Mn-SOD transcripts were ubiquitously detected in diverse tissues with variable levels of basal expression using an RT-PCR assay. Mn-SOD expression in the liver and kidney were significantly modulated by injection of LPS (1, 5, or 10 microg g(-1) body weight), Edwardsiella tarda challenge (5 x 10(3) or 5 x 10(5) cells/fish), and heavy metal exposure (Cd, Cu, or Zn at 5 microM). Results from this study suggest that Mn-SOD plays an important role in the host defence against oxidative damage caused by infection-mediated inflammation and/or toxicant related stress in this species.
对濒危淡水鱼类——蛇鮈（硬骨鱼纲，鲤形目）的锰超氧化物歧化酶（Mn-SOD）基因组结构进行了表征，并检测了Mn-SOD mRNA表达在各种刺激（如脂多糖（LPS）、细菌或重金属刺激）下的变化。蛇鮈Mn-SOD具有脊椎动物Mn-SOD保守的特征，包括同源的五部分基因结构（五个外显子被四个内含子打断）以及在编码区与脊椎动物直系同源基因具有高度序列同一性，包括典型的真核Mn-SOD特征。蛇鮈Mn-SOD基因的5'-调控上游区域缺乏典型的TATA序列；然而，它显示出各种转录因子结合元件，这些元件可能参与免疫和应激反应，以及介导金属和其他外源性物质代谢的酶的调节。对鱼类和哺乳动物基因组数据库中Mn-SOD基因的生物信息学分析揭示了脊椎动物谱系中Mn-SOD基因座的染色体同线性。使用RT-PCR检测法在不同组织中普遍检测到Mn-SOD转录本，其基础表达水平各不相同。通过注射LPS（1、5或10μg g(-1)体重）、迟缓爱德华氏菌刺激（5×10(3)或5×10(5)个细胞/鱼）和重金属暴露（5μM的Cd、Cu或Zn），肝脏和肾脏中的Mn-SOD表达受到显著调节。本研究结果表明，Mn-SOD在该物种抵御由感染介导的炎症和/或与毒物相关的应激所引起的氧化损伤的宿主防御中起重要作用。
