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Aaron Roznowski

Aaron Roznowski

Enter into the Ph.D. Program Fall 2012

Research Advisor: Bentley Fane

Research Topic: Structure/Function investigation of the bacteriophage φX174's DNA piloting protein Email: aroznowski@email.arizona.edu

Lab phone number: 621-5839

Many bacteriophage possess tail structures that pierce the bacterial cell wall during an infection. The viral genome then moves through the tail structure into the host cell. Bacteriophage ΦX174 displays strict icosahedral symmetry, lacking any visible tail structure. Instead, genome translocation is accomplished via DNA piloting proteins. The structure of this protein’s central domain was solved, revealing a tube composed of ten identical monomers. The portion of the monomer visible in the structure is composed of repeating amino acid sequences. In order to investigate the structure-function relationship of the repeating sequences, the gene was cloned and an eleven amino acid repeat was deleted. This construct was expressed during infection of wild type ΦX174 and its effects were analyzed. Expression of the deletion construct inhibits wild type ΦX174 plaque formation. In order to determine the cause of this inhibition, wild type virion formation was analyzed in lysis resistant cells expressing the construct. Lysates from infected cells were subjected to rate zonal sedimentation, and assembly products were analyzed. Induction of the construct prior to infection appears to inhibit virion synthesis and the resulting particles are less infectious. Induction 15 minutes post infection results in infectious viral particles. In both cases an unidentified protein sedimented with the virion.

Last updated 10 Sep 2014