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How do viruses infect cells?

Hu B, Margolin W, Molineux IJ and Liu J. The Bacteriophage T7 Virion Undergoes Extensive Structural Remodeling During Infection. Science. 2013; 339: 576-9.

Winn Feline Foundation has long been involved in funding research that studies how particular viruses infect cells. One example is the study from 2008 led by Dr. H. F. Egberink of the University of Utrecht in the Netherlands titled “ Identification of the cellular receptor for feline coronaviruses” (W08-006).

Researchers continue to learn more about how viruses infect cells or attach to cells to destroy them. Viruses that can destroy certain bacteria are called bacteriophages. It is known that a bacteriophage’s ability to take up and hold liquid on the surface of a solid along with ejection of their genome are important to their life cycle, yet their molecular mechanisms are not well understood.

In this study from the University of Texas, the authors used special electronic imaging (cryoelectron tomography) to capture T7 virions at successive stages of infection of the bacteria, Escherichia coli, minicells at ~4-nm resolution. Six tail fibers were folded against the central capsid, extending and orienting only after attaching and holding to the host cell surface. Receptor binding by the tail results in the insertion of an extended tail, which functions as the DNA ejection mechanism into the cell cytoplasm. After the DNA ejection, the extended tail collapses or dissembles, which allowed resealing of the infected cell membrane. [VT]