A chromosomal region of Mycoplasma agalactiae containing vsp-related genesundergoes in vivo rearrangement in naturally infected animals

A Mycoplasma agalactiae genomic fragment carrying Four vsp-related genes (d esignated avg: agalactiae variable genes) was cloned, sequenced and compare d to the vspA gene of Mycoplasma bovis. The following features were reveale d: (i) the presence of a highly conserved rsp 5' upstream region; (ii) a hi ghly homologous vsp N-terminal end encoding a putative lipoprotein signal s equence; (iii) sequence divergence of the rest of the mature proteins. By u sing avg specific probes in Southern blot analysis of genomic DNAs of M. ag alactiae strains as well as of isolates from infected animals, marked DNA p olymorphism of avg fragments was demonstrated. In addition, the avg genomic fingerprints were monitored for a period of 7 months, in isolates of M. ag alactiae from an individual chronically infected animal. The results provid ed evidence that a chromosomal region of M. agalactiae, carrying vsp-relate d genes, undergoes rearrangements in vivo in the natural animal host during the course of infection. (C) 2000 Federation of European Microbiological S ocieties. Published by Elsevier Science B.V. All rights reserved.