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Review
. 2000 Jul;182(14):3885-95.
doi: 10.1128/JB.182.14.3885-3895.2000.

The bases of crown gall tumorigenesis

J Zhu  1 , P M Oger, B Schrammeijer, P J Hooykaas, S K Farrand, S C Winans
Affiliations
Review

The bases of crown gall tumorigenesis

J Zhu et al. J Bacteriol. 2000 Jul.
No abstract available

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Figures

FIG. 1
FIG. 1
Genetic map of the octopine-type Ti plasmid. Nucleotide 1 is taken as the left end of the left border of TL. Genes transcribed from left to right are shown above the scale, while genes transcribed from right to left are shown below the scale. Known or suspected polycistronic operons are indicated with horizontal arrows. A 12.6-kb region deleted in the widely studied pTiA6NC is indicated by a horizontal bar on line 4. Regions that can form heteroduplexes with orthologous sequences of pTiC58 (27) are indicated with crosshatched bars. Green bars indicate genes that are located on the TL region or TR region and transferred to plant cells. Red bars indicate genes in the vir regulon, all of which are regulated by VirA and VirG, and many of which are required for T-strand processing and transfer. Purple bars indicate genes required for interbacterial conjugal transfer of the Ti plasmid. Light green bars indicate genes required for vegetative replication and partitioning of the Ti plasmid. Dark blue bars indicate genes encoding ATP binding cassette-type opine permeases, while light blue bars indicate opine catabolic genes. Orange bars indicate regulatory genes. Black bars indicate suspected IS elements (in this case, bars represent DNA sequence similarities rather than ORFs), while grey bars indicate ORFs of miscellaneous or unknown function. Gene names beginning with the letter “y” indicate the position of the gene, such that the second letter represents position in tens of kilobases, and the third letter indicates position in single kilobases. During the analysis of all these sequences, we found that tml, mas2′, mas1′, and ags had sequence discrepancies relative to orthologous genes from other Ti or Ri plasmids. These regions were resequenced after PCR amplification, and three errors in the original sequence (4) were detected and corrected. The resulting DNA sequence of the Ti plasmid has been deposited in the GenBank DNA sequence database (accession no. AF242881). Most Ti plasmid sequences were previously deposited in DNA sequence databases, and the original sources of these sequences are provided in the annotations of our compiled sequence.
FIG. 2
FIG. 2
Two-way exchange of chemical signals between A. tumefaciens and host plants. Wound-released chemical stimuli are perceived by the VirA to VirG proteins, which leads to transcription of vir promoters. T-DNA is processed by the VirD2 protein, and single-stranded linear T strands are formed by strand displacement. T strands and VirE2 are translocated from the bacteria via a pore encoded by the virB operon and form a T complex within the plant cytoplasm. T complexes are transported into the nucleoplasm via the host protein karyopherin alpha, and the T-DNA is integrated into genomic DNA. Transferred genes encode phytohormone synthases that lead to plant cell proliferation and opine synthases that provide nutrients to the colonizing bacteria. Opines are released from the plant cell, enter the bacteria via dedicated opine permeases, and are catabolized via opine-specific catabolic proteins. Opine permeases and catabolic enzymes are encoded by the Ti plasmid. For the sake of clarity, the relative orientations of vir genes and T-DNA have been inverted.
See this image and copyright information in PMC

References

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