| Literature References | 1. PICKETT, C.L., COTTLE, D.L., PESCI, E.C. AND BIKAH, G.
Cloning, sequencing, and expression of the Escherichia coli cytolethal
distending toxin genes.
INFECT.IMMUN. 62 1046-1051 (1994).
2. EYIGOR, I., DAWSON, K.A., LANGLOIS, B.E. AND PICKETT, C.L.
Cytolethal distending toxin genes in Campylobacter jejuni and Campylobacter
coli isolates; detection and analysis by PCR.
J.CLIN.MICROBIOL. 37 1646-1650 (1999).
3. DE RYCKE, J., SERT, V., COMAYRAS, C. AND TASCA, C.
Sequence of lethal events in HeLa cells exposed to the G2 blocking
cytolethal distending toxin.
EUR.J.CELL BIOL. 29 192-201 (2000).
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| Documentation | Escherichia coli, Haemophilus spp. and Campylobacter spp. all produce
a toxin that is seen to cause distension in certain cell lines [1,2],
which eventually disintegrate and die. This novel toxin, termed cytolethal
distending toxin (cdt), has three subunits: A, B and C. Their sizes are
approx. 27.7, 29.5 and 19.9kDa respectively [1], and they appear to be
entirely novel [2].
Further research on the complete toxin has revealed that it blocks the cell
cycle at stage G2, through inactivation of the cyclin-dependent kinase Cdk1
[3], and without induction of DNA breaks. This leads to multipolar abortive
mitosis and micronucleation, associated with centrosomal amplification [3].
The roles of each subunit are unclear, but it is believed that they have
separate roles in pathogenicity.
CDTOXINA is a 6-element fingerprint that provides a signature for cytolethal
distending toxin A proteins. The fingerprint was derived from an initial
alignment of 3 sequences: the motifs were drawn from conserved regions
spanning the full alignment length (~210 amino acids). Two iterations on
SPTR37_10f were required to reach convergence, at which point a true set
comprising 5 sequences was identified. A single partial match was also
found, Q46100, a CdtA protein from Campylobacter jejuni that matches motifs
1 and 5.
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