Article Figures & Data
Figures
- FIG 1
Lanthanides regulate mxa and xoxF genes divergently at the transcriptional level. Real-time qRT-PCR was performed on RNA harvested from M. buryatense 5GB1C cells grown in the presence or absence of supplemental 30 μM lanthanum (A) or 30 μM cerium (B), with and without copper. The values shown represent the fold change in mxa and xoxF gene expression from wild-type M. buryatense 5GB1C cells grown with lanthanides compared to wild-type M. buryatense 5GB1C cells grown without lanthanides. All CT values were normalized to 16S rRNA. Multiple-way analysis of variance (ANOVA) was performed to determine significance of changes in gene expression levels (***, P < 0.001; **, P < 0.01; *, P < 0.05). Asterisks above the x axis indicate significance between with- and without-lanthanide conditions. Asterisks below the x axis indicate significance between the two data points connected by the bar. (C) Whole-cell catechol 2,3-dioxygenase activity from the mxaF promoter reporter strain FC31 (METBUDRAFT_2794::PmxaF-xylE) grown in the indicated concentrations of supplemental lanthanum. Data represent means from three replicates ± standard deviations.
- FIG 2
Analysis of MDH (mxaF, mxaI, and xoxF) mutants. Growth curves for MDH mutant strains and wild-type M. buryatense 5GB1C grown without (A) and with (B) supplemental 30 μM lanthanum (La). Data represent means from three replicates ± standard deviations.
- FIG 3
Lanthanide switch is mediated in part by MxaB. (A) Growth curves for the ΔmxaB mutant and for wild-type M. buryatense 5GB1C grown without and with supplemental 30 μM lanthanum (La). (B) Real-time qRT-PCR was performed on RNA harvested from the ΔmxaB mutant and wild-type M. buryatense 5GB1C cells grown in the absence of lanthanum. Results shown represent the fold change in gene expression in the ΔmxaB mutant compared to wild-type M. buryatense 5GB1C grown without lanthanum. (C) Real-time qRT-PCR was performed on RNA harvested from the ΔmxaB mutant grown with and without supplemental 30 μM lanthanum. Results shown represent the fold change in gene expression in ΔmxaB cells grown with lanthanum compared to gene expression in ΔmxaB grown without lanthanum. Unpaired t tests were used to determine significance (***, P < 0.001; **, P < 0.01; *, P < 0.05) between gene expression levels in panels B and C. Data represent means from three replicates ± standard deviations.
- FIG 4
Suppressor mutation in ΔxoxFS mutant permits mxa expression in the presence of lanthanum (La). (A) Growth curves for ΔxoxFS strain and wild-type M. buryatense 5GB1C grown without and with supplemental 30 μM lanthanum. (B) Real-time qRT-PCR was performed on RNA harvested from the ΔxoxFS suppressor strain and wild-type M. buryatense 5GB1C grown in the presence of 30 μM supplemental lanthanum. Results represent the fold change in mxa gene expression in the ΔxoxFS strain compared to wild-type M. buryatense 5GB1C grown with lanthanum. (C) Real-time qRT-PCR was performed on RNA harvested from the ΔxoxFS suppressor strain grown in the presence of 30 μM supplemental lanthanum and wild-type M. buryatense 5GB1C grown without lanthanum. Results represent the fold change in mxa gene expression in ΔxoxFS grown with lanthanum compared to wild-type M. buryatense 5GB1C grown without lanthanum. Unpaired t tests were used to determine significance (***, P < 0.001) between gene expression levels in panels B and C. Data represent means from three replicates ± standard deviations.
Tables
Supplemental material
- Supplemental file 1 -
Supplemental materials and methods
Fig. S1, complementation of ΔmxaB restores wild-type lanthanum-dependent gene expression
Table S1, M. buryatense 5GB1C strains and plasmids
Table S2, primers
Table S3, doubling times of mutant and complementation strains
PDF, 1.2M
- Supplemental file 1 -
