Kryptolebias marmoratus(Poey, 1880): a potential model species for molecular carcinogenesis and ecotoxicogenomics

Abstract

Kryptolebias marmoratus(Rivulus marmoratustill 2004, order Cyprinodontoformes; family Rivulidae) is the only known self‐fertilizing hermaphrodite vertebrate. Because of this uniqueness, there has been great interest in its biology, physiology, developmental biology and genomics along with other basic and applied areas of environmental genomics and molecular carcinogenesis. In laboratory studies,K. marmoratushas shown susceptibility to a number of xenobiotics including carcinogens. Toxicologists are interested in the mechanisms of action of environmental chemicals of contemporary interest such as endocrine disruptors and may consider this as a suitable fish model for the study of chemically induced carcinogenesis. Single short‐term exposure to model chemical carcinogens is sufficient to induce tumourigenesis inK. marmoratusin a relatively short time span. In recent years, considerable data have been generated about gene sequences ofK. marmoratus. Laboratory maintenance ofK. marmoratusis relatively easy. Gene bank data are readily available, though not as extensive as for zebrafishDanio rerioor Japanese madakaOryzias latipes. The expressed sequence tag (EST) data, differential display real‐time reverse‐transcriptase polymerase chain reaction and Gene Sequencer 20™ sequencing data have recently been helpful in understanding the genomics and proteomics of this species. Recently, sequences of the oncogene,ras, and tumour suppressor gene,p53, have been reported inK. marmoratus. The expression of these important genes that play significant roles not only in carcinogenesis but also in other signal transduction pathways was observed to be modulated by environmental endocrine‐disrupting chemicals. Having a large sequence database (cDNA sequences and ESTs), it is expected that the use of a microarray in the near future will open new vistas for this fish with applications in cancer research, aquatic toxicology, endocrinology and genomics. This review discusses potential uses ofK. marmoratusin new biotechnological approaches of aquatic toxicology.