Terminal proteins of Streptomyces chromosome can target DNA into eukaryotic nuclei.
Streptomyces species are highly abundant soil bacteria that possess linear chromosomes (and linear plasmids). The 5' ends of these molecules are covalently bound by terminal proteins (TPs), that are important for integrity and replication of the telomeres. There are at least two types of TPs, both of which contain a DNA-binding domain and a classical eukaryotic nuclear localization signal (NLS). Here we show that the NLS motifs on these TPs are highly efficient in targeting the proteins along with covalently bound plasmid DNA into the nuclei of human cells. The TP-mediated nuclear targeting resembles the inter-kingdom gene transfer mediated by Ti plasmids of Agrobacterium tumefaciens, in which a piece of the Ti plasmid DNA is targeted to the plant nuclei by a covalently bound NLS-containing protein. The discovery of the nuclear localization functions of the Streptomyces TPs not only suggests possible inter-kingdom gene exchanges between Streptomyces and eukaryotes in soil but also provides a novel strategy for gene delivery in humans and other eukaryotes.
Tsai
Hsiu-Hui
HH
Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Shih-Pai, Taipei 112, Taiwan.
Huang
Chih-Hung
CH
Lin
Alan M
AM
Chen
Carton W
CW
D021581:Active Transport, Cell Nucleus; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism*; D002876:Chromosomes, Bacterial; D004261:DNA Replication; D004269:DNA, Bacterial / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D006801:Humans; D019913:Nuclear Localization Signals; D010957:Plasmids / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D013302:Streptomyces / Q000235:genetics*
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D019913:Nuclear Localization Signals; D011993:Recombinant Fusion Proteins