Open AccessAlternate phase variation in expression of two major surface membrane proteins (MBA and UU376) of Ureaplasma parvum serovar 3
Author(s) -
Zimmerman CarlUlrich R.,
Stiedl Thomas,
Rosengarten Renate,
Spergser Joachim
Publication year - 2009
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.2009.01505.x
Subject(s) - ureaplasma urealyticum , serotype , ureaplasma , biology , phase variation , gene , southern blot , microbiology and biotechnology , genetics , mycoplasma , virulence
Ureaplasma urealyticum and Ureaplasma parvum are commensals and pathogens of the human urogenital tract and of newborn infants. There are four distinct U. parvum serovars and 10 distinct U. urealyticum serovars. Both species possess a distinct immunodominant variable surface protein, the multiple banded antigen (MBA), which shows size variability among isolates as a result of changes in the number of C‐terminal repeating units. Adjacent to the MBA gene (UU375) lies UU376, which was annotated as ‘ Ureaplasma ‐specific conserved hypothetical gene’. In four different strains of U. parvum serovar 3, we demonstrated expression of UU376 by Western blot analysis and phase variation between UU376, here designated Upvmp376 ( Ureaplasma phase‐variable membrane protein 376), and MBA after application of selective pressure with hyperimmune antisera directed against either protein. By Southern blot analysis, we found that the switch between MBA and Upvmp376 expression is associated with a DNA inversion event in which the nonrepetitive region of the MBA gene and its putative promoter region are opposed to either the repetitive region of MBA or UU376. We propose that in U. parvum serovar 3, and presumably in all U. parvum and U. urealyticum , an inversion event at specific sites effects an alternate ON/OFF switching of the genes UU375 and UU376.