Vertebrate marine species as model systems for studying telomeres and telomerase.

Due to the limitations of in vitro human tissue culture systems, it has long been recognized that in vivo model organisms are critically necessary for studying important biological processes related to human disease. Telomere shortening and dysfunction have been shown as a contributing factor in aging using tissue culture systems and after 6 generations in inbred strains of mice. Currently, there are no models and little or no data defining the role of telomeres and telomerase in toxicological response, metal-induced carcinogenesis, or aging in marine animals. One of our primary objectives has been to determine if fish have similar utility to mouse models of aging and cancer, at least related to telomere biogenesis and telomerase function. We have found that the vast majority of tissues from marine species have functional telomerase activity, and that several of these vertebrates, although telomerase-expressing, have telomere lengths that resemble those found in human cells and tissues. Thus, because aquatic species have "normal" telomere sizes, marine animals may be more biologically relevant and cost-effective models for studying stem cells, aging, and cancer than inbred strains of rodents.