Conjugation with Acridines Turns Nuclear Localization Sequence into Highly Active Antimicrobial Peptide

The emergence of multidrug-resistant bacteria creates an urgent need for alternative antibiotics with new mechanisms of action. In this study, we synthesized a novel type of antimicrobial agent, Ac r_3-NLS, by conjugating hydrophobic acridines to the N-terminus of a nuclear localization sequence(NLS), a short cationic peptide. To further improve the antimicrobial activity of our agent, dimeric(Acr_3-NLS)_2 was simultaneously synthesized by joining two monomeric Acr_3-NLS together via a disulfide linker. Our results show that Acr_3-NLS and especially(Acr_3-NLS)_2 display signifi cant antimicrobial activity against gramnegative and gram-positive bacteria compared to that of the NLS. Subsequently, the results derived from the study on the mechanism of action demonstrate that Acr_3-NLS and(Acr_3-NLS)_2 can kill bacteria by membrane disruption and DNA binding. The double targets—cell membrane and intracellular DNA—will reduce the risk of bacteria developing resistance to Acr_3-NLS and(Acr_3-NLS)_2. Overall, this study provides a novel strategy to design highly eff ective antimicrobial agents with a dual mode of action for infection treatment.

M-CSF TARGETING INTO LCL NUCLEUS BEHAVES AS A MALIGNANCY PROMOTOR

Objective: To investigate the functions of nM-CSF in malignant cells. Methods: recombinant M-CSF was targeted into cell nucleus by employing a eukaryotic expression plasmid vector pCMV/myc/nuc. The constructed plasmid was transfected into cells of EBV transformed lymphoblastoid cell line (LCL). RT-PCR, Western blot and immunofluorescent staining showed that recombinant M-CSF was localized into LCL cell nucleus. The transgenic cells showed elevated proliferation potential, enhanced resistance to apoptosis and increased ability of in vitro migration. Conclusion: Nucleus presenting M-CSF might act as a promoting factor in the processes of cell malignancy.

ENHANCEMENT OF NIH3T3 CELL PROLIFERATION BY EXPRESSING MACROPHAGE COLONY STIMULATING FACTOR IN NUCLEI

Objective: To explore the effects of nuclear M-CSF on the process of tumorigenesis. Methods: Functional part of M-CSF cDNA was inserted into an eukaryotic expression plasmid pCMV/myc/nuc, which can add three NLS to the C-terminal of the expressed protein and direct the protein into the cell nuclei. The constructed plasmid was transferred into NIH3T3 cells and the cell clones were selected by G-418 selection. Cell clones stable expressing target protein were identified by RT-PCR, ABC immunohistochemistry assayand Western blot. Cell growth kinetics analyses throughgrowth curves, cell doubling time, MTT test and anti-sense oligodeoxynucleotide (ASODN) inhibiting cell growth testwere performed to identify cells proliferation potential.Results: The transfected cells showed elevated proliferation potential over the control cells. Conclusion: Abnormalappearance of M-CSF in nucleus could enhance cellproliferation, which suggests that cytokine isoforms within cell nucleus might play transcription factor-like role.