Goldstone J V, Hamdoun A, Cole B J, Howard-Ashby M, Nebert D W, Scally M, Dean M, Epel D, Hahn M E, Stegeman J J
Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA.
Dev Biol. 2006 Dec 1;300(1):366-84. doi: 10.1016/j.ydbio.2006.08.066. Epub 2006 Sep 3.
Metazoan genomes contain large numbers of genes that participate in responses to environmental stressors. We surveyed the sea urchin Strongylocentrotus purpuratus genome for homologs of gene families thought to protect against chemical stressors; these genes collectively comprise the 'chemical defensome.' Chemical defense genes include cytochromes P450 and other oxidases, various conjugating enzymes, ATP-dependent efflux transporters, oxidative detoxification proteins, and transcription factors that regulate these genes. Together such genes account for more than 400 genes in the sea urchin genome. The transcription factors include homologs of the aryl hydrocarbon receptor, hypoxia-inducible factor, nuclear factor erythroid-derived 2, heat shock factor, and nuclear hormone receptors, which regulate stress-response genes in vertebrates. Some defense gene families, including the ABCC, the UGT, and the CYP families, have undergone expansion in the urchin relative to other deuterostome genomes, whereas the stress sensor gene families do not show such expansion. More than half of the defense genes are expressed during embryonic or larval life stages, indicating their importance during development. This genome-wide survey of chemical defense genes in the sea urchin reveals evolutionary conservation of this network combined with lineage-specific diversification that together suggest the importance of these chemical stress sensing and response mechanisms in early deuterostomes. These results should facilitate future studies on the evolution of chemical defense gene networks and the role of these networks in protecting embryos from chemical stress during development.
后生动物基因组包含大量参与应对环境应激源的基因。我们在紫海胆基因组中搜索了被认为可抵御化学应激源的基因家族的同源物；这些基因共同构成了“化学防御组”。化学防御基因包括细胞色素P450和其他氧化酶、各种结合酶、ATP依赖性外排转运蛋白、氧化解毒蛋白以及调控这些基因的转录因子。在海胆基因组中，这类基因总计超过400个。转录因子包括芳烃受体、缺氧诱导因子、核因子红细胞衍生2、热休克因子以及核激素受体的同源物，这些在脊椎动物中调控应激反应基因。相对于其他后口动物基因组，一些防御基因家族，包括ABCC、UGT和CYP家族，在海胆中发生了扩增，而应激传感器基因家族则未显示出这种扩增。超过一半的防御基因在胚胎或幼体生命阶段表达，表明它们在发育过程中的重要性。此次对海胆化学防御基因的全基因组调查揭示了该网络的进化保守性以及谱系特异性多样化，这共同表明这些化学应激感知和反应机制在早期后口动物中的重要性。这些结果应有助于未来对化学防御基因网络进化以及这些网络在发育过程中保护胚胎免受化学应激作用的研究。
