부산대학교 도서관

Because of their widespread geographical distribution and high capacity of bioaccumulation, bivalve species, in particular blue mussels ( Mytilus edulis), are considered as sentinel organisms in Ecotoxicology for monitoring the effects of xenobiotics in estuaries and coastal areas. The purpose of this study was to identify molecular biomarkers for atrazine exposure by using differential analysis of gene expression. For this, the digestive gland transcriptome of atrazine exposed mussels (1 μg l−1, 24 h) was compared to that of control animals. Candidate transcripts for differential expression were isolated by Subtractive PCR Suppressive Hybridization (SSH). A total of 543 potentially regulated clones was isolated. A part of these clones was sequenced and extensive similarity searches in genome data bases were carried out. Among the sequenced cDNA clones, gld15, gld122 and gld177 which corresponded to potentially down regulated mRNA, were likely to encode for a Mytilus edulis DnaK-type molecular chaperone of the Heat shock 70 protein family. As a matter of fact, the deduced peptide sequence of gld15 comprised 223 amino acids and possessed 87.4% of identity with the human Hsc70. Heat shock proteins and, in particular Hsc70 and Hsp70, are considered as molecular chaperones involved in various cellular processes including refolding of damaged proteins and apoptosis. The fact that atrazine potentially down regulates the expression of a cytoprotective gene was unexpected and further experiments are required to measure the kinetics and dose response effects of atrazine on DnaK gene expression. Differential gene expression analysis is one of most widely used approach of the postgenomics era in the biomedical field of research and it may prove to be a valuable tool for the identification of new and relevant biomarkers in Ecotoxicology. [ABSTRACT FROM AUTHOR]