Zebrafish knockdowns

As genomic sequencing generates more potential target genes with unknown function, the need is increasing for model systems to evaluate the targets. While mice are reasonably relevant to human physiology, genetics and gene knockouts are difficult and time-consuming in mice. However, the zebrafish is emerging as a model system that combines vertebrate physiology, experimentally tractable development, and ease of generating large numbers of animals for genetic analysis (see BioCentury, Dec. 8). Last week researchers further increased the utility of this model organism, publishing a system in use by Progenitor Inc. and Ohio University (Athens, Ohio) that uses ribozymes to identify functions of known and unknown genes in zebrafish.

Ribozymes are enzymes composed of RNA that bind specific messenger RNA sequences and cut their substrate in half, preventing translation of the target message. Gene knockout technology, as is used in mice, is not available with zebrafish, but injection of ribozymes into zebrafish embryos may allow similar reductions in target gene expression. Since ribozymes act in the cytoplasm and do not require stable integration into the nucleus, ribozyme-based experiments also are much faster than gene knockouts...