title: Towards a synthetic chloroplast.
abstract: BACKGROUND
  The evolution of eukaryotic cells is widely agreed to have proceeded through a series of endosymbiotic events between larger cells and proteobacteria or cyanobacteria, leading to the formation of mitochondria or chloroplasts, respectively. Engineered endosymbiotic relationships between different species of cells are a valuable tool for synthetic biology, where engineered pathways based on two species could take advantage of the unique abilities of each mutualistic partner.
  
  
  RESULTS
  We explored the possibility of using the photosynthetic bacterium Synechococcus elongatus PCC 7942 as a platform for studying evolutionary dynamics and for designing two-species synthetic biological systems. We observed that the cyanobacteria were relatively harmless to eukaryotic host cells compared to Escherichia coli when injected into the embryos of zebrafish, Danio rerio, or taken up by mammalian macrophages. In addition, when engineered with invasin from Yersinia pestis and listeriolysin O from Listeria monocytogenes, S. elongatus was able to invade cultured mammalian cells and divide inside macrophages.
  
  
  CONCLUSIONS
  Our results show that it is possible to engineer photosynthetic bacteria to invade the cytoplasm of mammalian cells for further engineering and applications in synthetic biology. Engineered invasive but non-pathogenic or immunogenic photosynthetic bacteria have great potential as synthetic biological devices.
authors.affiliation: Department of Systems Biology, Harvard Medical School, Boston, Massachusetts, United States of America.
authors.forename: Christina M
authors.initials: CM
authors.lastname: Agapakis
authors.forename: Henrike
authors.initials: H
authors.lastname: Niederholtmeyer
authors.forename: Ramil R
authors.initials: RR
authors.lastname: Noche
authors.forename: Tami D
authors.initials: TD
authors.lastname: Lieberman
authors.forename: Sean G
authors.initials: SG
authors.lastname: Megason
authors.forename: Jeffrey C
authors.initials: JC
authors.lastname: Way
authors.forename: Pamela A
authors.initials: PA
authors.lastname: Silver
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics; D001483:Base Sequence; D002736:Chloroplasts; D004247:DNA / Q000235:genetics; D017931:DNA Primers; D019143:Evolution, Molecular; D005818:Genetic Engineering; D008264:Macrophages / Q000382:microbiology; D010788:Photosynthesis; D010957:Plasmids; D046940:Synechococcus / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D015027:Zebrafish / Q000196:embryology
chemical_list: D001426:Bacterial Proteins; D017931:DNA Primers; D004247:DNA