Retrotransposon Tf1 is targeted to Pol II promoters by transcription activators.
The LTR-retrotransposon Tf1 preserves the coding capacity of its host Schizosaccharomyces pombe by integrating upstream of open reading frames (ORFs). To determine which features of the target sites were recognized by the transposon, we introduced plasmids containing candidate insertion sites into S. pombe and mapped the positions of integration. We found that Tf1 was targeted specifically to the promoters of Pol II-transcribed genes. A detailed analysis of integration in plasmids that contained either ade6 or fbp1 revealed insertions occurred in the promoters at positions where transcription factors bound. Further experiments revealed that the activator Atf1p and its binding site were required for directing integration to the promoter of fbp1. An interaction between Tf1 integrase and Atf1p was observed, indicating that integration at fbp1 was mediated by the activator bound to its promoter. Surprisingly, we found Tf1 contained sequences that activated transcription, and these substituted for elements of the ade6 promoter disrupted by integration.
Leem
Young-Eun
YE
Section on Eukaryotic Transposable Elements, Laboratory of Gene Regulation and Development, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
Ripmaster
Tracy L
TL
Kelly
Felice D
FD
Ebina
Hirotaka
H
Heincelman
Marc E
ME
Zhang
Ke
K
Grewal
Shiv I S
SI
Hoffman
Charles S
CS
Levin
Henry L
HL
D002843:Chromatin / Q000737:chemistry / Q000378:metabolism; D021901:DNA, Intergenic / Q000737:chemistry / Q000235:genetics; D006597:Fructose-Bisphosphatase; D015966:Gene Expression Regulation, Fungal; D009690:Nucleic Acid Conformation; D016366:Open Reading Frames; D010957:Plasmids / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D012319:RNA Polymerase II / Q000235:genetics* / Q000378:metabolism; D018626:Retroelements / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D012568:Schizosaccharomyces / Q000235:genetics / Q000378:metabolism; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic
D002843:Chromatin; D021901:DNA, Intergenic; D018626:Retroelements; D029701:Saccharomyces cerevisiae Proteins; D029702:Schizosaccharomyces pombe Proteins; C495594:Bub1 protein, S pombe; D017346:Protein Serine-Threonine Kinases; D012319:RNA Polymerase II; C111172:FBP1 protein, S cerevisiae; D006597:Fructose-Bisphosphatase