Processing and joining of DNA ends coordinated by interactions among Dnl4/Lif1, Pol4, and FEN-1.
The repair of DNA double-strand breaks is critical for maintaining genetic stability. In the non-homologous end-joining pathway, DNA ends are brought together by end-bridging factors. However, most in vivo DNA double-strand breaks have terminal structures that cannot be directly ligated. Thus, the DNA ends are aligned using short regions of sequence microhomology followed by processing of the aligned DNA ends by DNA polymerases and nucleases to generate ligatable termini. Genetic studies in Saccharomyces cerevisiae have implicated the DNA polymerase Pol4 and the DNA structure-specific endonuclease FEN-1(Rad27) in the processing of DNA ends to be joined by Dnl4/Lif1. In this study, we demonstrated that FEN-1(Rad27) physically and functionally interacted with both Pol4 and Dnl4/Lif1 and that together these proteins coordinately processed and joined DNA molecules with incompatible 5' ends. Because Pol4 also interacts with Dnl4/Lif1, our results have revealed a series of pair-wise interactions among the factors that complete the repair of DNA double-strand breaks by non-homologous end-joining and provide a conceptual framework for delineating the end-processing reactions in higher eukaryotes.
Tseng
Hui-Min
HM
Molecular Medicine Graduate Program, Institute of Biotechnology, The University of Texas Health Sciences Center at San Antonio, San Antonio, Texas 78245, USA.
Tomkinson
Alan E
AE
D000123:Acetyltransferases; D001483:Base Sequence; D004247:DNA / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D004249:DNA Damage; D000072481:DNA Ligase ATP; D011088:DNA Ligases / Q000378:metabolism*; D019951:DNA Polymerase beta; D004260:DNA Repair; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism*; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*; D012689:Sequence Homology, Nucleic Acid
D008565:Membrane Proteins; D021122:Protein Subunits; D029701:Saccharomyces cerevisiae Proteins; D004247:DNA; D000123:Acetyltransferases; C107118:ELO2 protein, S cerevisiae; D019951:DNA Polymerase beta; D004259:DNA-Directed DNA Polymerase; C084892:POL4 protein, S cerevisiae; D011088:DNA Ligases; D000072481:DNA Ligase ATP