Ubiquitin expression in soft coral (Scleronephthya gracillimum) exposed to environmental stresses

Abstract

A cDNA clone encoding ubiquitin was isolated from the cDNA library of the soft coral Scleronephthya gracillimum, and changes in transcription of the ubiquitin gene induced by exposure to persistent organic pollutants and thermal stress were investigated using real-tune quantitative polymerase reaction analysis. The S. gracillimum ubiquitin gene spanned 384, lip and encoded 128 amino acids that exhibited 96% identity and 98% positives with ubiquitin in Acropora millepora or Drosophila melanogaster and 94% identity and 96% positives with human ubiquitin. Expression of the ubiquitin gene in S. graillimum was up-regulated approximately 4- to 7-fold during exposure to polycyclic aromatic hydrocarbons and was elevated significantly by thermal stress (28 degrees C) compared with control (22 degrees C) (P < 0.05). The stress-associated transcriptional changes indicated that the cellular defenses against environmental changes were activated in those animals through the up- or down-regulation of gene expression. The results also suggest that tibiquitin gene expression in response to stress may serve as a biomarker for monitoring levels of environmental contamination and the health status of animals in the local marine ecosystem.