Hosted by: Sharon Long
The Zambryski lab utilizes Agrobacterium tumefaciens as a model system to study type IV secretion systems (T4SS) and polar growth in bacteria. Agrobacterium is well known for its natural capacity to transfer DNA into plant cells whereupon it becomes stably integrated into nuclear DNA. T4SS are essential to transport DNA and proteins through the bacterial envelope into the plant cell. T4SS are evolutionarily conserved and also are utilized by numerous pathogenic bacteria that cause medically important diseases. Bacterial growth and division has been extensively investigated in model systems such as E.coli that grow by dispersed lateral insertion of new materials along the cell length. In contrast, Agrobacterium grows from a single pole of the bacterial cell. Polar growth in bacteria has not been well studied, and deserves significant attention as numerous pathogenic bacteria such as Gram-negative Rhizobiales (including Brucella and Bartonella) utilize this mode of growth. To date we have identified several proteins that exhibit dynamic localization to growth poles during the Agrobacterium cell cycle as observed by high resolution fluorescence microscopy. Interestingly, canonical division specific proteins such as FtsA and FtsZ, localize to the growth pole (in addition to the mid-cell) in Agrobacterium. Other proteins, such as PopZ and PodJ, that have been well studied in Caulobacter, exhibit growth pole or old pole specific localizations, respectively.