Figure 1. Induction of
ifas-1 expression upon infection is independent of STA-2 : A) Quantitative RT-PCR analysis of the expression of 10 genes that were reported to be induced by D. coniospora infection in RNAseq experiments. Levels of gene expression in wild type worms after 8 h of infection or in a strain expressing GPA-12gf under the control of a promoter active in the adult epidermis were compared to age-matched uninfected wild-type worms, mean results with SEM from 3 independent experiments are shown. B) Sequence alignment of IFAS-1, IFAS-2 and IFAS-3 proteins; the fascin domain is boxed in red. C) Quantitative RT-PCR analysis of the change in expression of 4 genes in wild type (blue) or
sta-2 mutant worms (red) after 8 h of infection compared to age-matched uninfected worms. Mean results with SEM from 3 independent experiments were analysed with a paired one-sided t test, * p < 0.05, ns non significant. D-F) Expression of
ifas-1 is observed in transgenic worms carrying an
ifas-1 transcriptional reporter. D) Representative confocal images with simultaneous visualisation of
ifas-1p::GFP in green,
myo-2p::mCherry from the coinjection marker in red, and autofluorescence in white (upper left panel) or only
ifas-1p::GFP in white (upper right panel; acquired with a spinning disk microscope). GFP expression can be seen in several neurons and in sheath cells in the head (upper panels) and in the tail (lower left panel), in the CAN, and HSN neurons (lower right panel); scale bar, 10 µm, nr, nerve ring, ph, pharynx, dc, dorsal cord, int, intestine, sh, sheath cells, vul, vulva. E) Images of young adult transgenic worms under normal culture conditions (left) or 4 h after wounding (right), where ca. 20% of the worm present a strong induction of
ifas-1p::GFP in the epidermis; scale bar, 500 µm. F) After 8 h of infection,
ifas-1p::GFP expression is induced in less than 10% of the population. The increased GFP expression is always seen in the epidermis (epi), as exemplified by the selected worms in the middle panel and one worm shown at higher magnification on the right, compared to control worms (left panel); scale bar, 500 µm in left and middle panels, 100 µm in the right panel.