Biomedical subjects

Scott R Blechinger

Publications and source records attributed to Scott R Blechinger.

3 recordsLinked to original sources

PubMed2003

Heat shock gene expression and function during zebrafish embryogenesis.

Recent work in the zebrafish, Danio rerio, indicates that heat shock genes are expressed in unique spatial patterns under non-stress conditions. In particular, hsp90alpha is expressed during the normal differentiation of striated muscle fibres, and hsp70-4 is expressed during normal lens development in the eye. Furthermore, disruption of the activity of either of these genes or their protein products gives rise to unique embryonic phenotypes that result from failures in proper somitic muscle development and lens development, respectively. Embryonic hsp70-4 expression is also activated in a cell-specific manner following heavy metal exposure. This has allowed for the development of a hsp70-4/eGFP reporter gene system in stable transgenic zebrafish that serves as a reliable yet extremely quick indicator of cell-specific toxicity in the context of the multicellular, living embryo.

Animals↗

PubMed2002

The heat-inducible zebrafish hsp70 gene is expressed during normal lens development under non-stress conditions.

In the present study, we show that the stress-inducible hsp70 gene in zebrafish is strongly and specifically expressed during normal lens formation from 28 to 38 hours post-fertilization, and is subsequently downregulated by 2 days of age. Only weak constitutive hsp70 mRNA signal was sporadically observed in other embryonic tissues. Similarly, transgenic fish carrying a 1.5 kb fragment of the hsp70 promoter linked to eGFP exhibited fluorescence only in the lens. In contrast, both the endogenous hsp70 gene and the transgene were strongly expressed throughout the embryo following heat shock at the same developmental stages.

Animals↗

PubMed2002

Developmental toxicology of cadmium in living embryos of a stable transgenic zebrafish line.

The toxic effects of cadmium and other heavy metals have been well established, and many of these and other environmental pollutants are known to be embryotoxic or teratogenic. However, it has proven difficult to identify individual cells that respond to toxicants among the wide range of cell populations in an intact animal, particularly during early development when cells are continually changing their molecular and physiologic characteristics as they differentiate. Here we report the establishment of an in vivo system that uses hsp70 gene activation as a measure of cadmium toxicity in living early larvae of transgenic zebrafish carrying a stably integrated hsp70-enhanced green fluorescent protein (eGFP) reporter gene. We demonstrate that eGFP expression in this strain of fish acts as an accurate and reproducible indicator of cell-specific induction of hsp70 gene expression. Furthermore, the transgene responds in a dose-dependent manner at concentrations similar to those observed for morphologic indicators of early-life-stage toxicity and is sensitive enough to detect cadmium at doses below the median combined adverse effect concentration and the median lethal concentration. The stable nature of this transgenic line should allow for extremely rapid and reproducible toxicologic profiling of embryos and larvae throughout development.

Animals↗