Fig. 1

Fig. 1 Yersinia ruckeri antifeeding prophage tail (Afp) translocation system and effects of the glycosyltransferase domain of Afp18.

(a) Organization of Afp genes from Yersinia ruckeri and Serratia entomophila with their predicted and ascribed protein domains. The toxin units are shown in red. Bottom: pairwise genomic gene analysis of aligned Afp gene clusters using mVISTA (http://genome.lbl.gov/vista). Indicated is the average per cent of nucleotide identity within a window of 20 nucleotides. Nucleotide identity >70% is shaded in red. (b) Architecture of Y. ruckeri Afp18 and similarity to the virulence gene product Afp18 from S. entomophila. Amino-acid sequence alignment of the region surrounding the DxD motif (marked) of different toxin glycosyltransferases. Secondary structure elements are deduced from the crystal structure of PaTox (pdb code 4MIX). Accession numbers are the following: P. asymbiotica PaTox (PaGT, accession number C7BKP9), Legionella pneumophila glucosyltransferase 1 (Lgt1, accession number Q5ZVS2), Clostridium difficile toxin B (TcdB, accession number P18177), C. sordellii lethal toxin (TcsL, accession number Q46342), C. novyi α-toxin (TcnA, accession number Q46149). Alignment was prepared using ClustalW and rendered using ESPript 3.0 (www.espript.ibcp.fr). Identical residues are boxed and shown in red, similar residues are boxed in yellow. (c) Live images of non-injected, PBS buffer control, Afp18^G NxN and Afp18^G protein (each 3 µM, 1 nl injection) injected zebrafish embryos at indicated developmental stages, 16-cell (1.5 h.p.f.), 256-cell (2.5 h.p.f.) and 30% epiboly (4.7 h.p.f.). Arrows mark blastomere cleavage furrows at 16-cell and 256-cell, embryos are oriented animal to the top. At the 16-cell stage, Afp18^G-injected embryo blastomeres show cleavage planes, while blastomeres fail to establish cell boundaries at the 256-cell stage. Control embryos at 30% epiboly develop normally compared with non-injected WT, while Afp18^G-injected embryos show disrupted blastoderm (arrowhead) or disintegrate completely (asterisk). Scale bar, 200 µm.