title: Localization of the plasmid-encoded proteins TraI and MobA in eukaryotic cells.
abstract: Conjugation mediates gene transfer not only between bacterial species but also from bacteria to yeast, plant, and animal cells. DNA transferred by conjugative plasmids from bacteria to eukaryotes must traverse subcellular membranes in the recipient before the transferred genes can be expressed and inherited. This process is most likely facilitated by putative DNA pilot proteins such as VirD2 of the Agrobacterium tumefaciens Ti plasmid. Here, we test this model as a general feature of trans-kingdom conjugation using the DNA-relaxases TraI and MobA of the IncP and IncQ groups. TraI localized unambiguously and uniformly to the nuclei of both yeast and human cells, whereas MobA displayed a range of subcellular localization patterns. The tendency to localize to the nucleus was not correlated with predicted nuclear localization sequence motifs in either protein, suggesting a lack of stringent requirements for nuclear localizing potential in pilot proteins mediating conjugative DNA transfer to eukaryotes. Further, our results indicate that nuclear localization ability may be more commonly associated with conjugative pilot proteins than previously recognized.
authors.affiliation: Centre for Integrated Research in Biosafety, School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch, New Zealand.
authors.forename: Mark W
authors.initials: MW
authors.lastname: Silby
authors.forename: Gayle C
authors.initials: GC
authors.lastname: Ferguson
authors.forename: Craig
authors.initials: C
authors.lastname: Billington
authors.forename: Jack A
authors.initials: JA
authors.lastname: Heinemann
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D003227:Conjugation, Genetic; D004265:DNA Helicases / Q000235:genetics / Q000378:metabolism*; D004269:DNA, Bacterial / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D005057:Eukaryotic Cells / Q000378:metabolism*; D022761:Gene Transfer, Horizontal; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006801:Humans; D007422:Intestines / Q000166:cytology; D010957:Plasmids / Q000145:classification / Q000235:genetics*; D021381:Protein Transport; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000235:genetics; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D014162:Transfection
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D011993:Recombinant Fusion Proteins; D015534:Trans-Activators; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins; C027093:TraI protein, E coli; D004265:DNA Helicases