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2. Proteus mirabilis gram negative, facultative anaerobe rod
causes infections in human urinary tract (pyelonephritis, kidney stones) followed by septicaemia
motile bacterium with peritrichous flagella
Morphology change in swarming process

3. Swarming proteus mirabilis
„bulls-eye“ swarming on solid surfaces & self identity

4. Boundary between P. mirabilis strain BB2000 and HI4320

5. Aim of study
Identification and characterization of the genetic mechanism that is responsible for bacterial self identity

6. Construction of p. mirabilis mutant library
randomized Tn5-transposon mutagenesis of rifampicin resistent p. miarabilis BB2000
Tn5-cat Shuttle vector
conjugal transfer by mating of E.coli [pUTminiTn5-Cm] and BB2000
cat
tnp: Transposase; mobRP4: conjugal transfer domain

7. Loss of self recognition I
Screening of 3600 transposon BB2000 mutants revealed one mutant with phenotypic loss of self recognition
„identification of self“ (Ids)

8. Loss of self recognition II
six gene cluster idsABCDEF carries information for „identification of self“

9. Phenotyping of individual idsABCDEF knock outs
idsB – idsF are required for self recognition !

10. Phenotyping of individual idsABCDEF knock outs in HI4320 background
idsB, idsC and idsF can be complemented by allels of different strains
idsD and idsE are essential for self recognition !

11. idsD and idsE encode identity determinants
….but the ids gene cluster is not the sole determinant of boundary formation !
boundary between BB2000+pidsHI4320 and HI4320+pidsBB2000

12. Conserved organization of ids gene cluster in other P
Conserved organization of ids gene cluster in other P. mirabilis isolates
idsABCDEF with nearly identical length and ~96% identity to homolog
idsD and idsE have variable domains in protein sequences

13. Additional putative idsE genes in genome of P. mirabilis HI4320

14. Model of self recognitation
idsA is not required for self identity; idsF overtakes function distinct from idsB
and idsC in self-nonself recognition; idsD and idsE are molecular self identifiers

15. Summary
gene locus idsABCDEF of P. mirabilis is important for self-nonself discrimination and boundary formation
Conserved ids gene cluster has been found in other proteus mirabilis strains
idsA is not required for parental recognition
idsB, idsC and idsF are interchangeable between strains
idsD and idsE are specific molecular identifiers that possess strain dependent variable domains
other ids homologs in bacterial genome may contribute to the self recognition process

16. Thank you for your attention

17. P. mirabilis boundaries

18. Transposition and pBBR-MCS2 shuttle vector for mutagenesis