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Updated: Jun 27, 2026
Transfection and Mutagenesis of Target Genes in Mosquito Cells by Locked Nucleic Acid-modified Oligonucleotides
Published on: December 26, 2010
Francisella genes required for replication in mosquito cells
Amanda Read1, Sigrid J Vogl, Karsten Hueffer
1Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK 99775, USA.
Abstract:
Francisella tularensis, a potential bioterrorism agent, is transmitted by arthropod vectors and causes tularemia in many mammals, including humans. Francisella novicida causes disease with similar pathology in mice. We show that F. novicida invades hemocyte-like cells of the SualB cell line derived from Anopheles gambiae and replicates vigorously within these cells. We used transposon knockouts of single genes of F. novicida to show that bacterial growth within these insect cells is dependent on virulence factors encoded in a bacterial pathogenicity island that has been linked to replication in mammalian macrophages. The virulence factors MglA, IglA, IglB, IglC, and IglD as well as PdpA and PdpB were necessary for efficient growth in insect cells, but PdpC and PdpD were not required. The SualB cell line presents a valuable model to study the interactions between this important pathogen and insect vectors.
Insights
Francisella novicida, a bacterium causing tularemia, effectively invades and replicates within insect cells. Virulence factors crucial for mammalian infection are also essential for growth in these insect vectors.
Area of Science:
- Microbiology
- Vector-borne diseases
- Pathogen-host interactions
Background:
- Francisella tularensis is a significant bioterrorism threat, transmitted by arthropod vectors and causing tularemia in mammals.
- Francisella novicida serves as a model organism, exhibiting similar pathology to F. tularensis in mice.
- Understanding pathogen interactions with insect vectors is critical for controlling disease transmission.
Purpose of the Study:
- To investigate the interaction of Francisella novicida with insect cells.
- To identify bacterial factors essential for F. novicida replication within insect vectors.
- To evaluate the utility of the Anopheles gambiae SualB cell line as a model for studying F. novicida-insect vector interactions.
Main Methods:
- Utilized the SualB cell line derived from Anopheles gambiae (mosquito) hemocytes.
- Employed transposon mutagenesis to generate single-gene knockout mutants of F. novicida.
- Assessed bacterial growth and replication within the SualB insect cell line.
Main Results:
- Francisella novicida successfully invaded and replicated within the SualB insect cell line.
- Bacterial growth in insect cells was dependent on virulence factors located on a pathogenicity island.
- Specific virulence factors, including MglA, IglA-D, PdpA, and PdpB, were essential for efficient replication in insect cells.
- PdpC and PdpD were not required for F. novicida growth in this insect cell model.
Conclusions:
- The SualB cell line is a valuable model for studying Francisella interactions with insect vectors.
- Virulence factors necessary for mammalian macrophage replication are also critical for F. novicida growth within insect cells.
- This research provides insights into the mechanisms of pathogen transmission by arthropod vectors.
