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The Mycoplasma hominis vaa gene displays a mosaic gene structure
Author(s) -
Boesen Thomas,
Emmersen Jeppe,
Jensen Lise T.,
Ladefoged Søren A.,
Thorsen Poul,
Birkelund Svend,
Christiansen Gunna
Publication year - 1998
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1046/j.1365-2958.1998.00906.x
Subject(s) - biology , gene , leucine zipper , genetics , homology (biology) , mycoplasma hominis , conserved sequence , sequence analysis , sequence alignment , mycoplasma , peptide sequence
Mycoplasma hominis contains a variable adherence‐associated ( vaa ) gene. To classify variants of the vaa genes, we examined 42 M. hominis isolates by PCR, DNA sequencing and immunoblotting. This uncovered the existence of five gene categories. Comparison of the gene types revealed a modular composition of the Vaa proteins. The proteins constituted a conserved N‐terminal part followed by a varying number of interchangeable cassettes encoding approximately 110 amino acids with conserved sequence boxes flanking the cassettes. The interchangeable cassettes showed a high mutual homology and a conserved leucine zipper motif. The smallest product contained only one cassette and the largest five. Additionally, two types of stop mutations caused by substitutions resulting in the expression of truncated Vaa proteins were observed. Our results expand the known potential of the Vaa system in generating antigen variation.