Evolution and Conservation of Predicted Inclusion Membrane Proteins in Chlamydiae

Abstract

Chlamydiaspp. are obligate intracellular pathogens that replicate within a vacuole termed the inclusion. Chlamydiae extensively modify the inclusion membrane via the insertion of chlamydial inclusion membrane proteins (Incs) which decorate the cytosolic face of the inclusion. We have assessed the overall relatedness and phylogeny of Incs in order to identify potential evolutionary trends. Despite a high degree of conservation among Incs withinC. trachomatisserovars, phylogenetic analysis showed that some Incs cluster according to clinical groupings suggesting that certain Incs may contribute to tissue tropism. Bioinformatic predictions identified Incs in five chlamydial species: 55 inC. trachomatis, 68 inC. felis, 92 inC. pneumoniae, 79 inC. caviae, and 54 inC. muridarum. Inc homologues were compared between chlamydial species and 23 core Incs were identified as shared among all species. Genomic expansion of Incs was identified inC. pneumoniae, C. caviae, andC. felisbut notC. trachomatisorC. muridarum.