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1 Department of Microbiology and Immunology, Yamaguchi University School of Medicine, 1-1-1 Minami-Kogushi, Ube, Yamaguchi 755-8505, Japan
2 Department of Clinical Research, National Sanyo Hospital, 685 Higashi-Kiwa, Ube, Yamaguchi 755-0241, Japan
Correspondence
Yoshinao Azuma
yazuma{at}yamaguchi-u.ac.jp
Mutsunori Shirai
mshirai{at}yamaguchi-u.ac.jp
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ABSTRACT |
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 TOP ABSTRACT INTRODUCTIONMETHODSRESULTSDISCUSSIONREFERENCES |
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A supplementary table and three supplementary figures are available with the online version of this paper.
Present address: Department of Veterinary Biosciences, the Ohio State University, 1900 Coffey Rd, Columbus, OH 43210, USA.
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INTRODUCTION |
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TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONREFERENCES |
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), asthma (Hahn et al., 1991) and Alzheimer's disease (Itzhaki et al., 2004). Persistence of chlamydial infection has been thought to be important for chronic diseases and has been characterized using model animals and activation stimuli such as cytokines and antibiotics (Beatty et al., 1993; Belland et al., 2003; Malinverni et al., 1995; Mehta et al., 1998). However, molecular-level relationships between chronic disease progression and persistent infection are not yet clear.
Chlamydiae exhibit a unique life cycle in which they alternate morphologies between elementary bodies (EBs) and reticulate bodies (RBs). EBs are transcriptionally inactive electron-dense particles that are internalized into host cells by inducing phagocytosis. EB differentiation into RBs occurs with the development of phagosomes into inclusions. Transcriptionally active RBs multiply by binary fission with nutrients acquired from the host cell. At the end of the developmental cycle, RBs are converted into EBs and released from host cells for the next infection. Besides the developmental cycle, during persistent infection caused by exposure to interferon gamma (IFN-
) or antibiotics, RBs differentiate into aberrantly large and non-multiplying RBs (Belland et al., 2003). However, little is known about the switching mechanism whereby vegetative RBs convert into infectious EBs or aberrant RBs. Understanding this molecular system should be helpful for the prevention of persistent chlamydial infection.
Two eukaryotic histone H1-like proteins of chlamydiae, Hc1 and Hc2, are present mainly in EBs, where those proteins bind DNA and promote genomic DNA condensation (Barry et al., 1992; Hackstadt et al., 1991; Perara et al., 1992; Tao et al., 1991). Recently a small regulatory RNA gene was identified as a suppressor of the lethal phenotype of hctA overexpression in Escherichia coli and it was shown to negatively regulate Hc1 synthesis at an early stage of infection (Grieshaber et al., 2006). These histone-like proteins may act as global transcriptional regulators and play a critical role for the transformation of vegetative RBs into infectious EBs. Transcriptional, translational and functional regulations of Hc1 and Hc2 may be important for the morphological switching. Chlamydial genome analyses have revealed the existence of another candidate gene as a regulator of Hc1 and Hc2, termed the set gene, which encodes a protein containing a domain similar to the eukaryotic SET domain (Stephens et al., 1998). Eukaryotic SET domains were initially identified in the C-terminal ends of Drosophila transcriptional regulatory factors (Alvarez-Venegas & Avramova, 2002; Jones & Gelbart, 1993; Kouzarides, 2002; Kuzmichev et al., 2005) and have been shown to be involved in chromatin remodelling due to histone methyltransferase activity to specific residues in amino-terminal histone tails, such as histone H3 K9 and K27 (Marmorstein, 2003.; Xiao et al., 2003).
Herein, we demonstrate that the chlamydial SET domain protein physically interacts with chlamydial histone-like proteins Hc1 and Hc2, and functions as a histone methyltransferase to methylate mouse histone H3 and Hc1. The results suggest involvement of the SET domain protein in chlamydial cell transformation from RBs to EBs.
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METHODS |
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TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONREFERENCES |
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HEp-2 cells (ATCC CCL-23) were used as host cells for infection by C. pneumoniae J138, isolated in Japan in 1994 (Shirai et al., 2000). C. pneumoniae J138 EBs were purified by sucrose-gradient centrifugation and stored at –80 °C in SPG buffer (pH 7.2), which consists of 250 mM sucrose, 10 mM sodium phosphate and 5 mM glutamate. Chlamydial titres were adjusted to 2.0x108 inclusion-formation units (i.f.u.) ml–1.
Chlamydial infection.
Chlamydial infections were performed by methods described previously (Rahman et al., 2005). Briefly, HEp-2 cells were grown in HEp-2 medium (Dulbecco's modified Eagle medium supplemented with 10 % heat-inactivated FCS and 50 µg gentamicin ml–1) at 37 °C, 5 % CO2. Prior to infection, 2.0x105 HEp-2 cells were seeded to each well of six-well tissue culture plates and allowed to adhere for 24 h. Infection was performed by addition of C. pneumoniae J138 EBs at 0.20 m.o.i., followed by centrifugation at 22 °C for 60 min at 700 g. After incubation for 30 min at 36 °C, 5 % CO2, the inocula were replaced with post-infection medium (Dulbecco's modified Eagle medium with 5 % heat-inactivated FCS, 50 µg gentamicin ml–1 and 1 µg cycloheximide ml–1). The infectants were incubated for up to 72 h at 36 °C, 5 % CO2.
Vector construction.
pGEX(2T-P)+cpnSET full-length and pGEX(2T-P)+cpnSET (206–219 aa) were constructed by cloning the C. pneumoniae J138 set gene fragments into pGEX(2T-P) (Azuma et al., 1995). Three deletion series of pGEX(2T-P)+Hc1 [Hc1-1 (aa 1–50), Hc1-2 (aa 41–78) and Hc1-3 (aa 65–123)] were constructed based on the pGEX(2T-P)+Hc1. For the yeast two-hybrid study, pGBKT7+cpnSET was prepared by cloning C. pneumoniae J138 set gene into pGBKT7 (Clontech). For construction of pGADT7+Hc1 and pGADT7+Hc2, C. pneumoniae J138 hctA and hctB genes, respectively, were cloned into pGADT7 (Clontech). Eight deletion series of pGBKT7-cpnSET were constructed by PCR using pGBKT7-cpnSET. pGEX4T-3-mG9a and pGEX4T-3-H3, encoding GST fusion G9a (621–1000 aa) and GST fusion histone H3 (1–50 aa), respectively, were kind gifts of Professor Yoichi Shinkai (Kyoto University, Kyoto, Japan) (Tachibana et al., 2001). All primers used in this work are shown in Supplementary Table S1, available with the online version of this paper.
Preparation of recombinant proteins and anti-cpnSET antiserum.
GST fusion proteins were produced in E. coli JM109 cells and purified using glutathione-agarose affinity purification in lysis buffer [20 mM Tris/HCl (pH 8.0), 5 mM EDTA, 0.5 % Triton X-100, 0.2 mM PMSF and a protease inhibitor mixture] (Azuma et al., 1993). One milligram of GST fusion cpnSET protein was cleaved with 0.02 U thrombin (Novagen) in thrombin reaction solution [20 mM Tris/HCl (pH 8.4), 150 mM NaCl, 2.5 mM CaCl2] for 2 h at 20 °C, and the thrombin was removed by incubation with 50 µl p-aminobenzamidene-agarose beads (Amersham) for 1 h at 4 °C. Anti-cpnSET rabbit polyclonal sera were prepared by immunization of rabbits five times every other week with 0.1 µg of the purified GST fusion cpnSET (aa 206–219) protein, following the method described previously (Miura et al., 2001).
Histochemical analysis.
After fixation with 100 % methanol for 60 min, the infectants were incubated with anti-C. pneumoniae-specific monoclonal antibody (RR402) and anti-cpnSET rabbit serum as described above for 60 min at 25 °C. After washing, cells were stained with FITC-conjugated goat anti-mouse antibody and Alexa 545-conjugated goat anti-rabbit antibody. Nucleic acids were stained with 2 µg Hoechst 33258 ml–1 for 10 min. Microscopic observation was performed with an LSM510 laser scanning confocal microscope (Zeiss).
Quantitative RT-PCR.
For quantitative RT-PCR by a LightCycler (Roche), QuantiTect SYBR Green RT-PCR (Qiagen) was used with a total RNA fraction extracted from C. pneumoniae-infected cells. Reactions were performed based on the manufacturer's instructions. All primers are shown as a supplementary table within the online version of this paper at Table S1 for primers.
Protein interaction analyses.
Yeast two-hybrid analysis was performed using MatchMaker GAL4 Two-Hybrid System 3 kits (Clontech) according to the manufacturer's instructions. Transformants were assayed by growth on plates without leucine, tryptophan and histidine, and without leucine and tryptophan as a control.
Structure modelling of cpnSET was carried out using the virus SET structure as a template (Eswar et al., 2003; Manzur et al., 2003) and peptide docking analysis onto cpnSET was performed using AutoDock (Morris et al., 1996).
In vitro histone methyltransferase assay.
Procedures for in vitro measurement of histone methyltransferase activity were adapted from the protocol reported previously (Tachibana et al., 2001). Briefly, the assay was carried out with 0.5 µg mG9a or cpnSET protein and 0.5 µg GST fusion mouse histone H3 or chlamydial Hc1 as a substrate in 50 µl reaction buffer (50 mM Tris/HCl pH 8.5, 20 mM KCl, 10 mM MgCl2, 10 mM 
-mercaptoethanol, 250 mM sucrose and 4.6 kBq S-adenosyl-[methyl-14C]-L-methionine as methyl donor). After incubation for 60 min at 37 °C, reactions were stopped by addition of 15 µl SDS buffer [6 % SDS, 150 mM Tris/HCl (pH 6.8), 300 mM DTT, 0.1 % BPB and 30 % (v/v) glycerol] and boiling at 100 °C for 10 min. Methyl-14C was detected using a BAS-2000 scanner (FujiFilm) after protein separation by 12 % acrylamide SDS-PAGE.
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RESULTS |
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TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONREFERENCES |
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; Carlson et al., 2005; Kalman et al., 1999; Read et al., 2000, 2003; Shirai et al., 2000; Stephens et al., 1998; Thomson et al., 2005). CPj0878 is assigned as a gene coding a SET domain protein in C. pneumoniae J138 and well conserved (overall more than 60 % identities) in the family Chlamydiaceae. The C-terminal SET domain shows approximately 30 % identities to many eukaryotic SET domains. The eukaryotic SET domains are well characterized as catalytic domains of histone methyltransferases involved in chromatin remodelling, especially transcriptional regulation and establishment of heterochromatin (Marmorstein, 2003.; Xiao et al., 2003). The chlamydial SET domain protein consists of two distinct domains, CDC39 and SET (Fig. 1a). The N-terminal one-third is partially similar to a CDC39/NotI component in a yeast general transcription-negative regulator CCR4–Not complex involved in controlling mRNA initiation (Liu et al., 1998). This CDC39 region is well conserved only in chlamydial SET domain proteins but not in other organism SET proteins. The C-terminal two-thirds region preserves SET signature motifs, such as S-adenosyl-L-methionine-binding sites and a catalytic site for the histone methyltransferase activity (Zhang et al., 2003).
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). But recent progress in genome analysis has revealed the existence of numbers of genes encoding SET-like domains in non-eukaryotic organisms, e.g. Paramecium bursaria chlorella virus-1 (Manzur et al., 2003), archaeal Methanosarcina mezei (Manzur & Zhou, 2005) and a variety of eubacterial phyla such as Firmicutes, Proteobacteria, Chlorobi, Spirochaetes and Chlamydiae. Phylogenetic analysis of eubacterial and other SETs illustrates that eubacterial SETs diverge into a few groups similar to the general taxological phyla (Fig. 1b
). It suggests that chlamydial set genes are not transferred horizontally from eukaryotic organisms, but rather likely diverged from a bacterial origin. The sequence alignment of SETs is shown as Supplementary Fig. S1 with the online version of this paper.
Gene expression and protein localization of cpnSET
Since the existence of the C. pneumoniae SET domain protein (cpnSET) was proposed based on prediction by genomic analysis, prior to functional analyses, its gene expression and protein localization were investigated by quantitative RT-PCR and immunohistochemical observation. Anti-cpnSET rabbit polyclonal serum prepared in this work was used to detect cpnSET protein in HEp-2 cells infected with C. pneumoniae J138. Simultaneously, anti-C. pneumoniae-specific monoclonal antibody RR402 and Hoechst 33258 were used for counter-staining. While chlamydial inclusions visualized by RR402 were detectable at any stages, cpnSET was detected only at 60 and 72 h post-infection (h.p.i.) (Fig. 2a) and in chlamydial cells (Fig. 2b). It is a similar expression pattern of Hc1 and Hc2 proteins encoded by hctA and hctB genes, respectively (Hackstadt et al., 1991).
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). In contrast to SET protein accumulation (Fig. 2a), chlamydial ftsK has been shown to express constantly from middle to late infection stages (Byrne et al., 2001) and our data from microarray analyses for chlamydial expression showed results consistent with this (data not shown). To clarify the expression of set, quantitative RT-PCR was performed. Relative expression of set, ompA, hctA and hctB normalized to 16S rRNA amount are shown in Fig. 3(b). Constant expression of ompA and late-stage expression of hctA and hctB were consistent with previous reports (Fahr et al., 1995; Slepenkin et al., 2003). The accumulation of set mRNA was increased simultaneously with hctA and hctB after 54 h.p.i., suggesting that set may be transcriptionally independent of ftsK and regulated in the same manner as hctA and/or hctB.
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). SET protein localization, expression stage and interaction with Hc1 and Hc2 strongly suggest that cpnSET catalyses protein methylation to Hc1 and Hc2 proteins. The original data for the yeast two-hybrid system are shown as Supplementary Fig. S2 with the online version of this paper.
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). A 0.5 µg sample of cpnSET, GST and G9a proteins was separately incubated with 0.5 µg recombinant mouse histone H3. It was shown that cpnSET can methylate histone H3 and the methylation activity of cpnSET is 14 % of G9a under these conditions (Fig. 4b).
As a substrate candidate of chlamydial proteins for cpnSET activity, Hc1 protein was subjected to this assay with Hc1-1, Hc1-2 and Hc1-3 (aa 1–50, 41–78 and 65–123, respectively). The full lengths of Hc1 and Hc2 are difficult to keep soluble in the processes of protein purification and methyltransferase reaction. As a result, only the Hc1-1 was capable of being methylated by cpnSET (Fig. 4c). No apparently conserved sequences were found between H3 (aa 1–50) and Hc1-1 (Fig. 4c). However, the combination of two informatics analyses, structure modelling of cpnSET using the virus SET structure and peptide docking analysis, indicates that K27 of H3, one of the specific methylation sites (Tachibana et al., 2001), and K29 of Hc1 were the best-fitting lysine residues to the catalytic space of cpnSET on the basis of the lowest docking energy. The modelled cpnSET structure and docking profile are shown in Supplementary Fig. S3 with the online version of this paper.
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DISCUSSION |
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TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONREFERENCES |
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(Manzur et al., 2003; Manzur & Zhou, 2005). Herein, cpnSET was shown to function as a protein methyltransferase to methylate both murine histone H3 and chlamydial Hc1 in vitro, suggesting that cpnSET may play an important role in modification of Hc1 proteins for the morphological change from RBs to EBs. Since localization of cpnSET was shown mainly in chlamydial cells, cpnSET may methylate Hc1 in vivo, but it is still possible that chlamydial SET proteins are exported into host cells or that host histones are transported into chlamydial cells, and then cpnSET and host histones functionally interact with each other. Identification of physiological substrates for methylation by cpnSET and, if Hc1 is one of the physiological substrates for methylation in vivo, elucidation of the significance of Hc1 protein modification remains for further investigation. Here one of the eubacterial SET domain proteins was revealed as a protein methyltransferase, and this finding suggests that other eubacterial SET domain proteins may function as methyltransferases as well.
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ACKNOWLEDGEMENTS |
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Edited by: J. Parkhill
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REFERENCES |
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|
TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONREFERENCES |
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Azuma, Y., Yamagishi, M. & Ishihama, A. (1993). Subunits of the Schizosaccharomyces pombe RNA polymerase II: enzyme purification and structure of the subunit 3 gene. Nucleic Acids Res 21, 3749–3754.
Azuma, Y., Tabb, M. M., Vu, L. & Nomura, M. (1995). Isolation of a yeast protein kinase that is activated by the protein encoded by SRP1 (Srp1p) and phosphorylates Srp1p complexed with nuclear localization signal peptides. Proc Natl Acad Sci U S A 92, 5159–5163.
Azuma, Y., Hirakawa, H., Yamashita, A., Cai, Y., Rahman, M. A., Suzuki, H., Mitaku, S., Toh, H., Goto, S. & other authors (2006). Genome sequence of the cat pathogen, Chlamydophila felis. DNA Res 13, 15–23.
Barry, C. E., Hayes, S. F. & Hackstadt, T. (1992). Nucleoid condensation in Escherichia coli that express a chlamydial histone homolog. Science 256, 377–379.
Beatty, W. L., Byrne, G. I. & Morrison, R. P. (1993). Morphologic and antigenic characterization of interferon gamma-mediated persistent Chlamydia trachomatis infection in vitro. Proc Natl Acad Sci U S A 90, 3998–4002.
Belland, R. J., Nelson, D. E., Virok, D., Crane, D. D., Hogan, D., Sturdevant, D., Beatty, W. L. & Caldwell, H. D. (2003). Transcriptome analysis of chlamydial growth during IFN-gamma-mediated persistence and reactivation. Proc Natl Acad Sci U S A 100, 15971–15976.
Byrne, G. I., Ouellette, S. P., Wang, Z., Rao, J. P., Lu, L., Beatty, W. L. & Hudson, A. P. (2001). Chlamydia pneumoniae expresses genes required for DNA replication but not cytokinesis during persistent infection of HEp-2 cells. Infect Immun 69, 5423–5429.
Carlson, J. H., Porcella, S. F., McClarty, G. & Caldwell, H. D. (2005). Comparative genomic analysis of Chlamydia trachomatis oculotropic and genitotropic strains. Infect Immun 73, 6407–6418.
Dillon, S. C., Zhang, X., Trievel, R. C. & Cheng, X. (2005). The SET-domain protein superfamily: protein lysine methyltransferases. Genome Biol 6, 227.[Medline]
Eswar, N., John, B., Mirkovic, N., Fiser, A., Ilyin, V. A., Pieper, U., Stuart, A. C., Marti-Renom, M. A., Madhusudhan, M. S. & other authors (2003). Tools for comparative protein structure modeling and analysis. Nucleic Acids Res 31, 3375–3380.
Fahr, M. J., Douglas, A. L., Xia, W. & Hatch, T. P. (1995). Characterization of late gene promoters of Chlamydia trachomatis. J Bacteriol 177, 4252–4260.
Grieshaber, N. A., Grieshaber, S. S., Fischer, E. R. & Hackstadt, T. (2006). A small RNA inhibits translation of the histone-like protein Hc1 in Chlamydia trachomatis. Mol Microbiol 59, 541–550.[CrossRef][Medline]
Hackstadt, T., Baehr, W. & Ying, Y. (1991). Chlamydia trachomatis developmentally regulated protein is homologous to eukaryotic histone H1. Proc Natl Acad Sci U S A 88, 3937–3941.
Hahn, D. L., Dodge, R. W. & Golubjatnikov, R. (1991). Association of Chlamydia pneumoniae (strain TWAR) infection with wheezing, asthmatic bronchitis, and adult-onset asthma. JAMA 266, 225–230.[Abstract]
Itzhaki, R. F., Wozniak, M. A., Appelt, D. M. & Balin, B. J. (2004). Infiltration of the brain by pathogens causes Alzheimer's disease. Neurobiol Aging 25, 619–627.[CrossRef][Medline]
Jones, S. R. & Gelbart, W. M. (1993). The drosophila polycomb-group gene enhancer of zeste contains a region with sequence similarity to trithorax. Mol Cell Biol 13, 6357–6366.
Kalman, S., Mitchell, W., Marathe, R., Lammel, C., Fan, J., Hyman, R. W., Olinger, L., Grimwood, J., Davis, R. W. & Stephens, R. S. (1999). Comparative genomes of Chlamydia pneumoniae and C. trachomatis. Nat Genet 21, 385–389.[CrossRef][Medline]
Kouzarides, T. (2002). Histone methylation in transcriptional control. Curr Opin Genet Dev 12, 198–209.[CrossRef][Medline]
Kuzmichev, A., Margueron, R., Vaquero, A., Preissner, T. S., Scher, M., Kirmizis, A., Ouyang, X., Brockdorff, N., Abate-Shen, C. & other authors (2005). Composition and histone substrate of polycomb repressive group complexes change during cellular differentiation. Proc Natl Acad Sci U S A 102, 1859–1864.
Liu, H. Y., Badarinarayana, V., Audino, D. C., Rappsilber, J., Mann, M. & Denis, C. L. (1998). The NOT proteins are part of the CCR4 transcriptional complex and affect gene expression both positively and negatively. EMBO J 17, 1096–1106.[CrossRef][Medline]
Malinverni, R., Kuo, C. C., Campbell, L. A. & Grayston, J. T. (1995). Reactivation of Chlamydia pneumoniae lung infection in mice by cortisone. J Infect Dis 172, 593–594.[Medline]
Manzur, K. L. & Zhou, M. M. (2005). An archaeal SET domain protein exhibits distinct lysine methyltransferase activity towards DNA-associated protein MC1-alpha. FEBS Let 579, 3859–3865.[CrossRef][Medline]
Manzur, K. L., Farooq, A., Zeng, L., Plotnikova, O., Koch, A. W., Sachchidanand & Zhou, M. M. (2003). A dimeric viral SET domain methyltransferase specific to Lys27 of histone H3. Nat Struct Biol 10, 187–196.[CrossRef][Medline]
Marmorstein, R. (2003). Structure of SET domain proteins: a new twist on histone methylation. Trends Biochem Sci 28, 59–62.[CrossRef][Medline]
Mehta, S. J., Miller, R. D., Ramirez, J. A. & Summersgill, J. T. (1998). Inhibition of Chlamydia pneumoniae replication in HEp-2 cells by interferon-gamma: role of tryptophan catabolism. J Infect Dis 177, 1326–1331.[Medline]
Miura, K., Inouye, S., Sakai, K., Takaoka, H., Kishi, F., Tabuchi, M., Tanaka, T., Matsumoto, H., Shirai, M. & other authors (2001). Cloning and characterization of adenylate kinase from Chlamydia pneumoniae. J Biol Chem 276, 13490–13498.
Morris, G. M., Goodsell, D. S., Huey, R. & Olson, A. J. (1996). Distributed automated docking of flexible ligands to proteins: parallel applications of AutoDock 2.4. J Comput Aided Mol Des 10, 293–304.[CrossRef][Medline]
Perara, E., Ganem, D. & Engel, J. N. (1992). A developmentally regulated chlamydial gene with apparent homology to eukaryotic histone H1. Proc Natl Acad Sci U S A 89, 2125–2129.
Rahman, M. A., Azuma, Y., Fukunaga, H., Murakami, T., Sugi, K., Fukushi, H., Miura, K., Suzuki, H. & Shirai, M. (2005). Serotonin and melatonin, neurohormones for homeostasis, as novel inhibitors of infections by the intracellular parasite Chlamydia. J Antimicrob Chemother 56, 861–868.
Read, T. D., Brunham, R. C., Shen, C., Gill, S. R., Heidelberg, J. F., White, O., Hickey, E. K., Peterson, J., Utterback, T. & other authors (2000). Genome sequences of Chlamydia trachomatis MoPn and Chlamydia pneumoniae AR39. Nucleic Acids Res 28, 1397–1406.
Read, T. D., Myers, G. S. A., Brunham, R. C., Nelson, W. C., Paulsen, I. T., Heidelberg, J., Holtzapple, E., Khouri, H., Federova, N. B. & other authors (2003). Genome sequence of Chlamydophila caviae (Chlamydia psittaci GPIC): examining the role of niche-specific genes in the evolution of the Chlamydiaceae. Nucleic Acids Res 31, 2134–2147.
Rosenfeld, M. E., Blessing, E., Lin, T. M., Moazed, T. C., Campbell, L. A. & Kuo, C. (2000). Chlamydia, inflammation, and atherogenesis. J Infect Dis 181 Suppl 3, S492–S497.[CrossRef]
Shirai, M., Hirakawa, H., Kimoto, M., Tabuchi, M., Kishi, F., Ouchi, K., Shiba, T., Ishii, K., Hattori, M. & other authors (2000). Comparison of whole genome sequences of Chlamydia pneumoniae J138 from Japan and CWL029 from USA. Nucleic Acids Res 28, 2311–2314.
Slepenkin, A., Motin, V., de la Maza, L. M. & Peterson, E. M. (2003). Temporal expression of Type III secretion genes of Chlamydia pneumoniae. Infect Immun 71, 2555–2562.
Stephens, R. S., Kalma, S., Lammel, C., Fan, J., Marathe, R., Aravind, L., Mitchell, W., Olinger, L., Tatusov, R. L. & other authors (1998). Genome sequence of an obligate intracellular pathogen of humans: Chlamydia trachomatis. Science 282, 754–759.
Tachibana, M., Sugimoto, K., Fukushima, T. & Shinkai, Y. (2001). SET-domain containing protein, G9a, is a novel lysine-preferring mammalian histone methyltransferase with hyperactivity and specific selectivity to lysines 9 and 27 of histone H3. J Biol Chem 276, 25309–25317.
Tao, S., Kaul, R. & Wenman, W. M. (1991). Identification and nucleotide sequence of a developmentally regulated gene encoding a eukaryotic histone H1-like protein from Chlamydia trachomatis. J Bacteriol 173, 2818–2822.
Thomson, N. R., Yeats, C., Bell, K., Holden, M. T., Bentley, S. D., Livingstone, M., Cerdeno-Tarrago, A. M., Harris, B., Doggett, J. & other authors (2005). The Chlamydophila abortus genome sequence reveals an array of variable proteins that contribute to interspecies variation. Genome Res 15, 629–640.
Xiao, B., Wilson, J. R. & Gamblin, S. J. (2003). SET domains and histone methylation. Curr Opin Struct Biol 13, 699–705.[CrossRef][Medline]
Zhang, X., Yang, Z., Khan, S. I., Horton, J. R., Tamaru, H., Selker, E. U. & Cheng, X. (2003). Structural basis for the product specificity of histone lysine methyltransferases. Mol Cell 12, 177–185.[CrossRef][Medline]
Received 12 June 2006;
revised 20 October 2006;
accepted 20 October 2006.
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), hctA (
), hctB (
) and ompA (
) genes were normalized with 16S rRNA. Relative expression was calculated as the ratio to the value of the expression of each gene at 24 h.