Secretion

Secretion systems, which can be mediating the passage of macromolecules across cellular membranes, are essential for virulent and genetic material exchange among bacteria species. There are at least six specialized secretion systems in bacteria (Figure 1).

T4SS

Type IV secretion system (T4SS) is one of important secretion systems, usually consisting of 12 components, that are, VirB1, VirB2 …VirB11 and VirD4. T4SS plays various functions in transporting a wide range of components, from single protein to protein-protein and protein-DNA complexes. Among them, the most important is its ability of mediating the conjugative transfer of plasmid DNA or transposons, which lead to the spread of antibiotic-resistant or pathogenic genes among a wide range of bacterial species. And, T4SS could also operate bacteria to inject effectors into host cells during infection. Figure 2 and Figure 3 respectively display T4SS structure in Gram-negative and Gram-positive bacteria.

T4SP

The Type IV Secretion Project (T4SP) is an integrative system for finding all VirB/D genes associated with T4SS in bacterial genomes. The latest version of the T4SP contains a total of 717 experimentally verified VirB/D genes, 6191VirB/D genes predicted based on genomic location and homology, and 51,067 homologs of VirB/D genes in 5239 bacterial strains. The T4SP database also contains information on the distribution of these VirB/D genes in each genome and other pertinent information (e.g., gene number, gene name, gene type, position, sequence, related articles, quick links to other webs and so on).

Version

Current release:

Release 3.0, Aug 06, 2015

♦ 717 experimental verified VirB/D genes with related reference were incorporated into the T4SP.

♦ The database is updated: VirB/D genes in 5239 bacterial strains

♦ New taxonomy database imported from NCBI.

♦ The display of result page was revised.

♦ Online Blast function

♦ Online T4SS gene and gene cluster prediction function was added

Past release:

Release 2.0, Sep 06, 2011

♦ 717 experimental verified VirB/D genes with related reference were incorporated into the T4SP.

♦ The database is updated: VirB/D genes in 107 chromosome and 916 plasmids of bacterial strains were added.

♦ New taxonomy database imported from NCBI.

♦ The display of result page was revised.Thanks for suggestions of Michael Galperin, Executive Editor, NAR Database Issue.

Release 1.1, June 27, 2011

♦ Update web properties in T4SP system to shorten the response time.

♦ The mirror website was set up (http://t4ss.genetyping.org)

♦ A new website test in a small group (44 people)

Release 1.0, June 22, 2011

♦ VirB/D genes in 1171 chromosomes of bacterial strains were incorporated in the first version of T4SP database.

Disclaimer:

T4SP is an original database product, copyright Bioinformatics Department of China CDC. Although best efforts are always applied when developing T4SP products, we makes no warrant nor assumes any legal responsibility for the accuracy or usefulness of T4SP or any information contained therein.