Dimerization of VirD2 Binding Protein Is Essential for Induced Tumor Formation in Plants

English version České info

Agrobacterium tumefaciens causes crown gall disease (tumors) in agriculturally important plant species. It initiates infection through its Ti plasmid, which integrates a portion of its own DNA (T-DNA) into that of the host genome. The T-DNA is bound to VirD2 relaxase, and this complex is required for the efficient translocation and integration of the T-DNA into the plant genome for tumor formation. Two additional proteins, among others, are also required for Agrobacterium tumorigenesis: VirD4-coupling protein (CP) and VirD2-binding protein (VBP). VBP is responsible for recruiting VirD2–T-DNA to VirD4 CP to help localize T-DNA to the Type IV Secretion System apparatus for transfer. However, it is still unclear how VBP recruits the complex to VirD4 CP. Here, we report the crystal structure and associated functional studies of the C-terminal domain of VBP. We show that the C-terminal domain is the dimerization domain of VBP and only dimeric VBP is functional and essential for the induction of tumor in plants. This study enhances the understanding of the role of VBP in recruiting VirD2–T-DNA in A. tumefaciens prior to its transfer into the host plant. This mode of action can be extended to other pathogenic bacteria employing similar secretion systems.

Vyšlo v časopise: Dimerization of VirD2 Binding Protein Is Essential for Induced Tumor Formation in Plants. PLoS Pathog 10(3): e32767. doi:10.1371/journal.ppat.1003948
Kategorie: Research Article
prolekare.web.journal.doi_sk: https://doi.org/10.1371/journal.ppat.1003948

Souhrn

Zdroje

1. CascalesE, ChristiePJ (2003) The versatile bacterial type IV secretion systems. Nat Rev Microbiol 1: 137–149.

2. Alvarez-MartinezCE, ChristiePJ (2009) Biological diversity of prokaryotic type IV secretion systems. Microbiol Mol Biol Rev 73: 775–808.

3. LesslM, LankaE (1994) Common mechanisms in bacterial conjugation and Ti-mediated T-DNA transfer to plant cells. Cell 77: 321–324.

4. ChristiePJ, AtmakuriK, KrishnamoorthyV, JakubowskiS, CascalesE (2005) Biogenesis, architecture, and function of bacterial type IV secretion systems. Annu Rev Microbiol 59: 451–485.

5. TzfiraT, CitovskyV (2000) From host recognition to T-DNA integration: the function of bacterial and plant genes in the Agrobacterium-plant cell interaction. Mol Plant Pathol 1: 201–212.

6. AtmakuriK, CascalesE, BurtonOT, BantaLM, ChristiePJ (2007) Agrobacterium ParA/MinD-like VirC1 spatially coordinates early conjugative DNA transfer reactions. EMBO J 26: 2540–2551.

7. CascalesE, ChristiePJ (2004) Definition of a bacterial type IV secretion pathway for a DNA substrate. Science 304: 1170–1173.

8. GuoM, JinS, SunD, HewCL, PanSQ (2007) Recruitment of conjugative DNA transfer substrate to Agrobacterium type IV secretion apparatus. Proc Natl Acad Sci U S A 104: 20019–20024.

9. ChristiePJ (1997) Agrobacterium tumefaciens T-complex transport apparatus: a paradigm for a new family of multifunctional transporters in eubacteria. J Bacteriol 179: 3085–3094.

10. OkamotoS, Toyoda-YamamotoA, ItoK, TakebeI, MachidaY (1991) Localization and orientation of the VirD4 protein of Agrobacterium tumefaciens in the cell membrane. Mol Gen Genet 228: 24–32.

11. HamiltonCM, LeeH, LiPL, CookDM, PiperKR, et al. (2000) TraG from RP4 and TraG and VirD4 from Ti plasmids confer relaxosome specificity to the conjugal transfer system of pTiC58. J Bacteriol 182: 1541–1548.

12. KumarRB, DasA (2002) Polar location and functional domains of the Agrobacterium tumefaciens DNA transfer protein VirD4. Mol Microbiol 43: 1523–1532.

13. VeluthambiK, ReamW, GelvinSB (1988) Virulence genes, borders, and overdrive generate single-stranded T-DNA molecules from the A6 Ti plasmid of Agrobacterium tumefaciens. J Bacteriol 170: 1523–1532.

14. AtmakuriK, DingZ, ChristiePJ (2003) VirE2, a type IV secretion substrate, interacts with the VirD4 transfer protein at cell poles of Agrobacterium tumefaciens. Mol Microbiol 49: 1699–1713.

15. CitovskyV, GDEV, ZambryskiP (1988) Single-Stranded DNA Binding Protein Encoded by the virE Locus of Agrobacterium tumefaciens. Science 240: 501–504.

16. TzfiraT, CitovskyV (2002) Partners-in-infection: host proteins involved in the transformation of plant cells by Agrobacterium. Trends Cell Biol 12: 121–129.

17. TzfiraT, VaidyaM, CitovskyV (2004) Involvement of targeted proteolysis in plant genetic transformation by Agrobacterium. Nature 431: 87–92.

18. GuoM, HouQ, HewCL, PanSQ (2007) Agrobacterium VirD2-binding protein is involved in tumorigenesis and redundantly encoded in conjugative transfer gene clusters. Mol Plant Microbe Interact 20: 1201–1212.

19. MooreLW, ChiltonWS, CanfieldML (1997) Diversity of opines and opine-catabolizing bacteria isolated from naturally occurring crown gall tumors. Appl Environ Microbiol 63: 201–207.

20. AltschulSF, MaddenTL, SchafferAA, ZhangJ, ZhangZ, et al. (1997) Gapped BLAST and PSI-BLAST: a new generation of protein database search programs. Nucleic Acids Res 25: 3389–3402.

21. HolmL, RosenstromP (2010) Dali server: conservation mapping in 3D. Nucleic Acids Res 38: W545–549.

22. KozlovG, DenisovAY, GirardM, DicaireMJ, HamlinJ, et al. (2011) Structural basis of defects in the sacsin HEPN domain responsible for autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS). J Biol Chem 286: 20407–20412.

23. PitzschkeA, HirtH (2010) New insights into an old story: Agrobacterium-induced tumour formation in plants by plant transformation. EMBO J 29: 1021–1032.

24. GrynbergM, ErlandsenH, GodzikA (2003) HEPN: a common domain in bacterial drug resistance and human neurodegenerative proteins. Trends Biochem Sci 28: 224–226.

25. DangTA, ZhouXR, GrafB, ChristiePJ (1999) Dimerization of the Agrobacterium tumefaciens VirB4 ATPase and the effect of ATP-binding cassette mutations on the assembly and function of the T-DNA transporter. Mol Microbiol 32: 1239–1253.

26. HoSN, HuntHD, HortonRM, PullenJK, PeaseLR (1989) Site-directed mutagenesis by overlap extension using the polymerase chain reaction. Gene 77: 51–59.

27. OliverDJ, XiangCB, HanP, LutzigerI, WangK (1999) A mini binary vector series for plant transformation. Plant molecular biology 40: 711–717.

28. DoubliéS (1997) Preparation of selenomethionyl proteins for phase determination. Methods Enzymol 276: 523–530.

29. TerwilligerTC, BerendzenJ (1997) Bayesian correlated MAD phasing. Acta Crystallogr D Biol Crystallogr 53: 571–579.

30. Otwinowski Z, Minor W (1997) Processing of X-ray diffraction data collected in oscillation mode. In: Carter Jr, CW, editor. Methods in enzymology. London: Elsevier Academic press. pp. 307–326.

31. TerwilligerT (2003) SOLVE and RESOLVE: automated structure solution and density modification. Methods Enzymol 374: 22–37.

32. EmsleyP, CowtanK (2004) Coot: model-building tools for molecular graphics. Acta Crystallogr D Biol Crystallogr 60: 2126–2132.

33. MurshudovGN, SkubakP, LebedevAA, PannuNS, SteinerRA, et al. (2011) REFMAC5 for the refinement of macromolecular crystal structures. Acta Crystallogr D Biol Crystallogr 67: 355–367.

34. BrownPH, SchuckP (2006) Macromolecular size-and-shape distributions by sedimentation velocity analytical ultracentrifugation. Biophys J 90: 4651–4661.

35. ZupanJR, ZambryskiP (1995) Transfer of T-DNA from Agrobacterium to the plant cell. Plant Physiol 107: 1041–1047.

36. CitovskyV, KozlovskySV, LacroixB, ZaltsmanA, Dafny-YelinM, et al. (2007) Biological systems of the host cell involved in Agrobacterium infection. Cell Microbiol 9: 9–20.