Phosphorylation regulates integration of the yeast Ty5 retrotransposon into heterochromatin.
The yeast Ty5 retrotransposon preferentially integrates into heterochromatin at the telomeres and silent mating loci. Target specificity is mediated by a small domain of Ty5 integrase (the targeting domain, TD), which interacts with the heterochromatin protein Sir4 and tethers the integration complex to target sites. Here we demonstrate that TD is phosphorylated and that phosphorylation is required for interaction with Sir4. The yeast cell, therefore, through posttranslational modification, controls Ty5's mutagenic potential: when TD is phosphorylated, insertions occur in gene-poor heterochromatin, thereby minimizing deleterious consequences of transposition; however, in the absence of phosphorylation, Ty5 integrates throughout the genome, frequently causing mutations. TD phosphorylation is reduced under stress conditions, specifically starvation for amino acids, nitrogen, or fermentable carbon. This suggests that Ty5 target specificity changes in response to nutrient availability and is consistent with McClintock's hypothesis that mobile elements restructure host genomes as an adaptive response to environmental challenge.
Dai
Junbiao
J
Department of Genetics, Development, and Cell Biology, 1035A Roy J. Carver Co-Laboratory, Iowa State University, Ames, IA 50011-3650, USA.
Xie
Weiwu
W
Department of Genetics, Development, and Cell Biology, 1035A Roy J. Carver Co-Laboratory, Iowa State University, Ames, IA 50011-3650, USA.
Brady
Troy L
TL
Department of Genetics, Development, and Cell Biology, 1035A Roy J. Carver Co-Laboratory, Iowa State University, Ames, IA 50011-3650, USA.
Gao
Jiquan
J
Department of Genetics, Development, and Cell Biology, 1035A Roy J. Carver Co-Laboratory, Iowa State University, Ames, IA 50011-3650, USA.
Voytas
Daniel F
DF
Department of Genetics, Development, and Cell Biology, 1035A Roy J. Carver Co-Laboratory, Iowa State University, Ames, IA 50011-3650, USA. Electronic address: voytas@iastate.edu.
D019943:Amino Acid Substitution; D001665:Binding Sites / Q000235:genetics; D004271:DNA, Fungal / Q000235:genetics / Q000378:metabolism; D006570:Heterochromatin / Q000235:genetics / Q000378:metabolism; D019426:Integrases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008954:Models, Biological; D010766:Phosphorylation; D018626:Retroelements / Q000235:genetics*; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism*; D012694:Serine / Q000737:chemistry; D038281:Silent Information Regulator Proteins, Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D020798:Two-Hybrid System Techniques
D004271:DNA, Fungal; D006570:Heterochromatin; D018626:Retroelements; C061573:SIR4 protein, S cerevisiae; D038281:Silent Information Regulator Proteins, Saccharomyces cerevisiae; D012694:Serine; D019426:Integrases