The retrovirus HIV is the major disease causing member of the long terminal repeat (LTR)-containing retroelements. To understand the mechanisms that retroviruses use to propagate, we study LTR-retrotransposons, a closely related variety of retroelement that exists in model organisms such as yeast. The LTR-retrotransposon we study is the Tf1 element of the fission yeast, Schizosaccharomyces pombe. The focus of our efforts is to understand the molecular details of mechanisms such as reverse transcription, transport of Tf1 into the nucleus, and the integration of Tf1 cDNA. We apply the techniques of yeast genetics to study the functions of the transposon encoded proteins as well as the contributions of host encoded factors.