Appl Environ Microbiol 2002, 68:673–690.PubMedCrossRef Authors’ contributions LH conceived and designed the study, collected and prepared the tissues, performed Fluorescence Givinostat ic50 In Situ Hybridisation and drafted the manuscript. TKJ and LM assisted in designing the study, making microscopic images, performed the cloning and sequencing and drafted the manuscript. SNO participated in designing the study and helped draft the manuscript. All authors read and approved the

final manuscript.”
“Background Chlamydia trachomatis is an intracellular bacterium that can multiply only within a host cell. Reticulate bodies (RBs) are the replicating form of Chlamydia bacteria that transform into infectious elementary bodies (EBs) prior to cell lysis. The transformation from a fragile RB to a robust EB is dramatic: the size reduces from 1 μm to 0.3 μm, the dispersed chromatin aggregates into a condensed nucleoid and metabolism ceases. C. trachomatis is classified into 19 serotypes (A-L3) based on the major outer membrane protein (MOMP) where PFT�� research buy A-C cause trachoma, D-K cause urogenital infections and L1-L3 cause lymphogranuloma venereum (LGV). Hc1 and Hc2 are DNA-binding proteins, homologous to eukaryotic histone H1 [1, 2] which are thought to mediate the chromatin compaction. These histone-like proteins are encoded by the hctA and hctB genes that are expressed late in the life cycle when

RBs convert to EBs [3]. The hctA gene Suplatast tosilate has been inserted into Escherichia coli and the expressed Hc1 was shown to induce a compaction of chromatin into a spherical condensed nucleoid [4]. Hc2 also condenses DNA but the nucleoid is distinctly different with a more thoroid shape [5, 6], indicating that these proteins interact with DNA in different ways. Both proteins are able to repress transcription, but Hc2 has a higher binding affinity for RNA and thus represses translation more efficiently than Hc1 [6]. The Hc1 protein has two domains: the conserved N-terminus [7], which mediates dimerisation, and the lysine-rich C-terminus, which is responsible for DNA binding [8,

9]. Hc2, on the other hand, varies in size between serovars because of varying numbers of lysine-rich pentameric repeats [10]. Hc2 appears to be ubiquitous in Chlamydiaceae because the hctB gene has been found in all available genome sequences of this family, Based on Southwestern blot analysis, Hc2 has previously been reported to be absent or present in reduced amounts in Chlamydophila psittaci Tariquidar strain Mn [10]. However, the hctB gene has been found in C. psittaci strain 6BC by whole genome sequencing (G. Myers, personal communication). The hctB gene encoding Hc2 is one of the targets in a newly developed multilocus sequence typing (MLST) system for C. trachomatis [11]. Studies of trachoma, lymphogranuloma venereum (B.