Schizosaccharomyces pombe retrotransposon Tf2 mobilizes primarily through homologous cDNA recombination.
The Tf2 retrotransposon, found in the fission yeast Schizosaccharomyces pombe, is nearly identical to its sister element, Tf1, in its reverse transcriptase-RNase H and integrase domains but is very divergent in the gag domain, the protease, the 5' untranslated region, and the U3 domain of the long terminal repeats. It has now been demonstrated that a neo-marked copy of Tf2 overexpressed from a heterologous promoter can mobilize into the S. pombe genome and produce true transposition events. However, the Tf2-neo mobilization frequency is 10- to 20-fold lower than that of Tf1-neo, and 70% of the Tf2-neo events are homologous recombination events generated independently of a functional Tf2 integrase. Thus, the Tf2 element is primarily dependent on homologous recombination with preexisting copies of Tf2 for its propagation. Finally, production of Tf2-neo proteins and cDNA was also analyzed; surprisingly, Tf2 was found to produce its reverse transcriptase as a single species in which it is fused to protease, unlike all other retroviruses and retrotransposons.
Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.
E F
EF
Hoff
H L
HL
Levin
J D
JD
Boeke
D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics*; D004271:DNA, Fungal / Q000235:genetics; D010450:Endopeptidases / Q000235:genetics; D005656:Fungal Proteins / Q000235:genetics*; D015966:Gene Expression Regulation, Fungal / Q000235:genetics; D012333:RNA, Messenger / Q000378:metabolism; D012194:RNA-Directed DNA Polymerase / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics; D011995:Recombination, Genetic / Q000235:genetics*; D018626:Retroelements / Q000235:genetics*; D012568:Schizosaccharomyces / Q000378:metabolism*; D029702:Schizosaccharomyces pombe Proteins; D017422:Sequence Analysis, DNA
D018076:DNA, Complementary; D004271:DNA, Fungal; D005656:Fungal Proteins; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D018626:Retroelements; D029702:Schizosaccharomyces pombe Proteins; C083145:Tf2-6 protein, S pombe; D012194:RNA-Directed DNA Polymerase; D010450:Endopeptidases