Fig. 5: Null mutants for two released peptidases show reduced quorum sensing. | Nature Communications

Fig. 5: Null mutants for two released peptidases show reduced quorum sensing.

From: Extracellular release of two peptidases dominates generation of the trypanosome quorum-sensing signal

Fig. 5

a PCR analysis of genomic DNA derived from null mutants of Tb927.8.7020, Tb927.11.2500 and Tb927.11.12850 analysed using gene-specific primers. Several null mutant clones were analysed in each case, together with wild-type parental parasites. For each target gene no amplicon was detected with the null mutant clones, whereas a band of the expected size was detected using gDNA from wild-type parasites. Integrity of the gDNA in each case was validated using primers targeting a control gene (lower panels). b Parasitaemias (mean ± SEM) of infections initiated with null mutant line (red) or parental line (blue) for each target gene. Biologically independent replicate infections are shown (n = 2), with Tb927.11.2500 and Tb927.11.12850 showing elevated parasitaemia. Note that the scales differ on the y axis between graphs. c Upper panel- PCR confirmation of the successful add back of a copy of Tb927.11.12850 to the null mutant. Lower panel- parasitaemias (mean ± SEM) of biologically independent infections initiated with parental T. brucei AnTat 1.1 parasites (yellow, n = 2), a Tb927.11.12850 null mutant (red, n = 3), or the Tb927.11.12850 null mutant containing an add back for the gene (blue, n = 2). The null mutant exhibited elevated parasitaemia reflecting reduced differentiation, whereas the add back of the Tb927.11.12850 gene restored the growth profile to levels similar to the parental line. d PAD1 expression of parasites at day 5, 6 and 7 post infections. The null mutant exhibited reduced PAD1 expression at peak parasitaemia compared to the parental cells or add back line in biologically independent analyses (respectively n = 3, n = 2, n = 2). Beyond day 5, PAD1 levels were similar between lines, reflecting that the null mutant exhibited delayed but not abrogated stumpy formation, with stumpy parasites further enriched due to their enhanced tolerance of the developing immune response beyond day 5. Source data are provided as a source data file.

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