Fv1, the mouse retrovirus resistance gene.

A number of genes which affect the susceptibility of mice to infection by retroviruses have been described. One of the most interesting of these genes is Fv1 (Friend virus susceptibility 1), which acts at a stage in the retroviral life-cycle following virus entry into the cell but prior to integration and formation of proviral structures. A detailed understanding of the mode of action of Fv1 might be expected to shed fresh light on early steps of the retroviral replication, although progress has been slow in this area due to uncertainty about the nature of the Fv1 gene. The recent cloning of Fv1 by a positional approach fills this gap in current knowledge. Fv1 appears to be derived from a fragment of a retroviral genome, an observation that may suggest novel approaches to the control of retroviral replication.