Walleye dermal sarcoma virus reverse transcriptase is temperature sensitive.

Walleye dermal sarcoma virus (WDSV) is a piscine retrovirus that replicates naturally in fish at temperatures near 4 degrees C. The reverse transcriptase (RT) protein from virus particles isolated from walleye tumours was purified and biochemically characterized. Like the RT of the distantly related murine leukaemia virus, WDSV RT sediments as a monomer in the absence of template. It exhibits a K(m) of 22 microM for TTP in an assay with poly(rA) as a template and oligo(dT) as a primer. The enzyme is rapidly inactivated at temperatures greater than 15 degrees C. The ratio of RT activity at 15 degrees C to that at 4 degrees C is similar for WDSV and recombinant human immunodeficiency virus type 1, suggesting that, at least with this template, the fish enzyme is not specially adapted to function more efficiently in the cold.