Fig. 8: TOPAI regulating EcTopoI-RNAPs association to relieve TRCs.

a The cell mortality and doubling time of strains FMX783T1, FMX783T2 and FMX783Y1. The box plots showing the minima, maxima, center, bounds of box and whiskers and percentile. b Co-IP and BiFC experiments were conducted to verify that TOPAI combined with EcTopoI. BiFC system consisting of YN155 (amino acid positions 1−155 in Venus, where amino acid position 65 is mutated from F to L, a point mutation that promotes the maturation of fluorescent proteins) and VC156 (amino acid positions 156-239 in Venus). c The supercoiling of strain FMX783T2 (FMX783-TOPAI⁺) by adding 2.5 μg/mL chloroquine. d Association of TOPAI with the core promoter of RNAP was determined by ChIP analysis and RT-PCR to measure occupancy. e EU-labeled old RNA and new RNA of strains FMX783 and FMX892. Abbreviations: FMX783T1, FMX783-ΔTOPAI; FMX783T2, FMX783-TOPAI⁺; FMX783Y1, FMX783-YjhQ⁺, Co-IP, Co-Immunoprecipitation; BiFC, bimolecular fluorescence complementation; EcTopoI, Topoisomerase I of E. coli. Significance (P-value) was evaluated by two-sided t-test. Significant differences were marked as *P < 0.05, **P < 0.01 and ***P < 0.001. Values are shown as mean ± s. d. from three biological replicates. Source data are provided as a Source Data file.