Fig. 1: SAOUHSC_00406/TslA is encoded at a conserved gene cluster and secreted by the T7SS.

a SAOUHSC_00406/TslA is encoded on the νSaα island, at a locus also known as the LPL0 lipoprotein gene cluster. A variable number of SAOUHSC_00405/TilA homologues are encoded upstream of this cluster across different S. aureus strains, in RN6390 there are two (SAOUHSC_00402 and SAOUHSC_00404). b The four gene cassette is encoded in Listeria grayi and enterococcal genomes. c Homologues of SAOUHSC_00406/tslA can be found at a further two loci, LPLI and LPLIII, in a strain-dependent manner. Where strains do not encode a paralogue, the tla1 (SAOUHSC_00407-like) and tla2 (SAOUHSC_00408-like) genes are also absent, but variable numbers of til1 (SAOUHSC_00405-like) genes are present. To date no SAOUHSC_00406 paralogue is found at the LPLII locus which always appears to encode a single, phylogenetically diverse Til1 protein²⁴ (see also Supplementary Fig. 7). d Schematic representation of the split nanoluciferase assay to detect T7SS-dependent secretion. e The pep86 fragment of nanoluciferase was fused to the indicated protein of interest (denoted with an underline) and expressed from plasmid pRAB11 in strain USA300 or an otherwise isogenic essC mutant as described in the methods. To 100 µl of whole cell samples, 11S fragment of nanoluciferase and furimazine were added, and luminescence readings taken over a 10 min time course. Peak readings were used to calculate relative luminescence of the wild type compared to the essC mutant strain as described in the methods. Data are presented as the mean ± SD (n = 3 biologically independent experiments). Readings for supernatant and cytoplasmic fractions from these samples are displayed in Supplementary Fig. 3a, b and the raw data from these experiments is shown in Supplementary Fig. 4. Source data are provided as a Source Data file.