Papers, explained in our own words

1. Cytoplasmic Transport and Nuclear Import of Plasmid DNA

Haiqing Bai, Gillian M. Schiralli Lester, Laura C. Petishnok, David A. Dean

Productive gene transfer requires plasmid DNA to not only enter cells but also traffic through the cytoplasm and cross the nuclear envelope. Most transfection strategies focus on membrane entry and promoter choice, but cytoplasmic trafficking and nuclear import are critical, rate-limiting barriers—especially because cytoplasmic nucleases degrade DNA and the nuclear envelope restricts entry in non-dividing cells. --- - Cytoplasmic degradation: Plasmid DNA is degraded in HeLa and COS cell cytoplasm with a half-life of 50–90 min. - Protein–DNA complex: Over 600 proteins associate with the pEGFPN1 plasmid in transfected cells; complexes are dynamic, with some proteins binding for at least 4 h and others associating/disassociating over time. - Diffusion limit: DNA larger than 2000 bp is effectively unable to diffuse through cytoplasm in a physiological time frame due to cytoskeletal networks. - Directed movement: Plasmids containing CREB-bin