Nature Genetics
21, 385 - 389 (1999)
doi:10.1038/7716
Comparative genomes of Chlamydia pneumoniae and C. trachomatis
Sue Kalman1, Wayne Mitchell2, 3, Rekha Marathe1, Claudia Lammel2, Jun Fan1, Richard W Hyman1, Lynn Olinger2, 3, Jane Grimwood3, Ronald W Davis1
& Richard Stephens2, 31
Stanford DNA Sequencing and Technology Center, Stanford
University, Stanford, California 94305,
USA. 2
Program in Infectious Diseases, University of California,
Berkeley, California 94720, USA. 3
Francis I. Proctor Foundation, University of California,
San Francisco, California 94143, USA.
Correspondence should be addressed to Richard Stephens ctgenome@socrates.berkeley.edu
Chlamydia are obligate intracellular eubacteria that are phylogenetically
separated from other bacterial divisions. C. trachomatis and C.
pneumoniae are both pathogens of humans but differ in their tissue tropism
and spectrum of diseases. C. pneumoniae is a newly recognized species
of Chlamydia that is a natural pathogen of humans1, and
causes pneumonia and bronchitis. In the United States, approximately 10% of
pneumonia cases and 5% of bronchitis cases are attributed to C. pneumoniae
infection2. Chronic disease may result following respiratory-acquired
infection, such as reactive airway disease3, adult-onset asthma4 and potentially lung cancer5. In addition, C. pneumoniae
infection has been associated with atherosclerosis6,
7,
8,
9,
10,
11.
C. trachomatis infection causes trachoma, an ocular infection that leads
to blindness, and sexually transmitted diseases such as pelvic inflammatory
disease, chronic pelvic pain, ectopic pregnancy and epididymitis12.
Although relatively little is known about C. trachomatis biology13, even less is known concerning C. pneumoniae. Comparison
of the C. pneumoniae genome with the C. trachomatis genome14 will provide an understanding of the common biological processes
required for infection and survival in mammalian cells. Genomic differences
are implicated in the unique properties that differentiate the two species
in disease spectrum. Analysis of the 1,230,230-nt C. pneumoniae genome
revealed 214 protein-coding sequences not found in C. trachomatis,
most without homologues to other known sequences. Prominent comparative findings
include expansion of a novel family of 21 sequence-variant outer-membrane
proteins, conservation of a type-III secretion virulence system, three serine/threonine
protein kinases and a pair of parologous phospholipase-D-like proteins, additional
purine and biotin biosynthetic capability, a homologue for aromatic amino
acid (tryptophan) hydroxylase and the loss of tryptophan biosynthesis genes.
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