Suppressive subtraction libraries to identify interferon-inducible genes in fish.

Previous attempts to identify genes in fish that respond to virus infection or interferon induction have not been particularly productive. Since these genes are very important in developing strategies to control disease outbreaks in aquaculture, we began a study of interferon-inducible genes in fish using suppressive subtraction hybridization to construct cDNA libraries enriched for interferon-inducible genes. Subtraction hybridization libraries were constructed with cDNA obtained from the kidney, spleen, and liver of Chinook salmon (Oncorhynchus tshawytscha) and staghorn sculpin (Hemilepidotus spinosus) before and after injection with poly IC, a potent interferon inducer. The "identified" genes in both cDNA libraries corresponded to previously identified genes of the fish complement system, the interferon-inducible proteins observed in mammalian cells, and the Vig-1 gene, identified in fish cells after infection with fish rhabdoviruses.