Adenovirus serotype 5 (Ad5) is a double-stranded DNA virus that can cause upper respiratory infections and conjunctivitis. One of the viral proteins, E4 11k, supports early viral infection by promoting late gene expression. E4 11k has been shown to disrupt cellular function by relocalizing processing body (p body) proteins to cytoplasmic aggresomes. Aggresomes are perinuclear formations that are sites of misfolded protein storage and only arise when there is cellular stress. The scaffolding p body protein, Ddx6, has been shown to colocalize with E4 11k in aggresomes during a wild-type Ad5 infection. Ddx6, however, was not relocalized to chemically induced (cadmium chloride-treated) aggresomes. This suggests that E4 11k is necessary for the relocalization of Ddx6. We observed the localization of additional p body proteins (Lsm1, Edc3, and Pat1b) in human lung carcinoma cells (A549) following wild-type Ad5 infection and cadmium chloride (CdCl2) treatment. Lsm1 and Edc3 were relocalized to both infection and chemically induced aggresomes. Pat1b was not relocalized to either infection or chemically induced aggresomes, however, the number of cytoplasmic foci increased under both conditions. To further characterize the role of E4 11k in p body localization, we infected A549 cells with Ad5 E4 11k only, L103A mutant, and D105A-L106A mutant viruses. L103A and D105A-L106A are mutants that affect the multimerization of E4 11k and consequently its function. It is known that the L103A mutant cannot oligomerize but has the ability to dimerize. We then harvested the cells and used immunofluorescence staining to visualize the p body proteins with a confocal microscope. Preliminary results indicate that oligomerization is not required for infection induced aggresomal formation. E4 11k was found in aggresomes during an L103A infection, however, Ddx6 was not. The significance of this study is to understand better the dynamics of p body and aggresome formation in human lung cells.


GCSU Biological and Environmental Sciences Department, Transformative Experience Grant, GC Journey's Mini Grant, Academic Affairs Small Grant, and John E. Sallstrom Honors College

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