Front Microbiol. 2016 Dec 1;7:1929. eCollection 2016.

Cysteine-Mediated Gene Expression and Characterization of the CmbR Regulon in Streptococcus pneumoniae.

Afzal M1, Manzoor I1, Kuipers OP2, Shafeeq S3.

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In this study, we investigated the transcriptomic response of Streptococcus pneumoniae D39 to cysteine. Transcriptome comparison of the D39 wild-type grown at a restricted concentration of cysteine (0.03 mM) to one grown at a high concentration of cysteine (50 mM) in chemically-defined medium (CDM) revealed elevated expression of various genes/operons, i.e., spd-0150, metQ, spd-0431, metEF, gshT, spd-0618, fhs, tcyB, metB-csd, metA, spd-1898, yvdE, and cysK, likely to be involved in the transport and utilization of cysteine and/or methionine. Microarray-based data were further confirmed by quantitative RT-PCR. Promoter lacZ-fusion studies and quantitative RT-PCR data showed that the transcriptional regulator CmbR acts as a transcriptional repressor of spd-0150, metEF, gshT, spd-0618, tcyB, metA, and yvdE, putatively involved in cysteine uptake and utilization. The operator site of CmbR in the promoter regions of CmbR-regulated genes is predicted and confirmed by mutating or deleting CmbR operator sites from the promoter regions of these genes.


CmbR; Cysteine; MetA; MetE; pneumococcus

PMID: 27990139 PMCID: PMC5131005 DOI: 10.3389/fmicb.2016.01929

[PubMed - in process]