sequence of the acidic repeat protein (arp) gene differentiates venereal from nonvenereal Treponema pallidum subspecies, and the gene has evolved under strong positive selection in the subspecies that causes syphilis

• Published in: FEMS immunology and medical microbiology Vol. 53; no. 3; pp. 322 - 332
• Main Authors: Harper, Kristin N, Liu, Hsi, Ocampo, Paolo S, Steiner, Bret M, Martin, Amy, Levert, Keith, Wang, Dongxia, Sutton, Madeline, Armelagos, George J
• Format: Journal Article
• Language: English
• Published: Oxford, UK Oxford, UK : Blackwell Publishing Ltd 01.08.2008; Blackwell Publishing Ltd; Blackwell; Oxford University Press
• Subjects: Amino Acid Sequence; Animals; arp; Bacterial diseases; Bacterial diseases of the genital system; Bacterial infections; Bacterial Proteins; Bacterial Proteins - genetics; Bacteriology; Base Sequence; Biological and medical sciences; chemistry; classification; Disease transmission; DNA, Bacterial; DNA, Bacterial - chemistry; DNA, Bacterial - genetics; Epidemiology; Evolution, Molecular; Fundamental and applied biological sciences. Psychology; genetics; Genomes; Human bacterial diseases; Humans; Immune system; Infectious diseases; Medical sciences; Microbiology; Miscellaneous; Molecular Sequence Data; Polymorphism, Genetic; Positive selection; Rabbits; repeat region; Repetitive Sequences, Nucleic Acid; Sequence Analysis, DNA; Sequence Homology, Amino Acid; Sexually transmitted diseases; STD; Syphilis; Syphilis - microbiology; Syphilis - transmission; transmission; Treponema; Treponema - classification; Treponema - genetics; Treponema pallidum; typing; Yaws; typing; syphilis; yaws; repeat region; Skin disease; Typing; Spirochaetales; Microbiology; Acidic protein; Repeated sequence; Yaws; Treponematosis; Infection; Sexually transmitted disease; Immunology; Gene; Spirochaetosis; Syphilis; Bacteriosis; Bacteria; Treponemataceae; arp; Treponema pallidum
• ISSN: 0928-8244; 1574-695X; 2049-632X
• DOI: 10.1111/j.1574-695X.2008.00427.x

Despite the completion of the Treponema pallidum genome project, only minor genetic differences have been found between the subspecies that cause venereal syphilis (ssp. pallidum) and the nonvenereal diseases yaws (ssp. pertenue) and bejel (ssp. endemicum). In this paper, we describe sequence variation in the arp gene which allows straightforward differentiation of ssp. pallidum from the nonvenereal subspecies. We also present evidence that this region is subject to positive selection in ssp. pallidum, consistent with pressure from the immune system. Finally, the presence of multiple, but distinct, repeat motifs in both ssp. pallidum and Treponema paraluiscuniculi (the pathogen responsible for rabbit syphilis) suggests that a diverse repertoire of repeat motifs is associated with sexual transmission. This study suggests that variations in the number and sequence of repeat motifs in the arp gene have clinical, epidemiological, and evolutionary significance.