The essential role of the CopN protein in Chlamydia pneumoniae intracellular growth

The bacterium Chlamydia pneumoniae is a major cause of lung infections and is also associated with arteriosclerosis, heart disease and stroke. Work with this pathogen has been hampered by the lack of genetic tools, which among other things has made it difficult to identify virulence factors. Jin Huang et al. by-passed this problem by expressing five suspected C. pneumoniae virulence proteins in yeast cells. One of these proteins, known as CopN, interfered with cell division when expressed in yeast and mammalian cells. Then two compounds were found that reversed the cell division effect, and protected mammalian cells form infection by C. pneumoniae. This 'functional knockout' strategy offers an alternative to the direct genetic approach for use in deciphering the function of other Chlamydia proteins in disease.