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. 2014 Dec 23;5(6):e01858-14. doi: 10.1128/mBio.01858-14

FIG 3 .

FIG 3 

The AD gene cluster of S. pneumoniae is regulated by ArgR2. (A) Genetic regions of the three ArgR-type transcriptional regulators encoded in the TIGR4 genome. Regions: SP_0892, type I restriction enzyme; SP_0893, transcriptional regulator of arginine metabolism ArgR2; SP_0894, X-prolyl-dipeptidyl aminopeptidase gene pepX; SP_1200, GTP-binding protein LepA; SP_1201, serine/threonine protein phosphatase; SP_1202, DNA repair protein RecN; SP_1203, transcriptional regulator of arginine metabolism AhrC; SP_1204, 23S rRNA (cytidine1920-2′-O)/16S rRNA (cytidine1409-2′-O)-methyltransferase; SP_1205, geranyltranstransferase; SP_2075, ABC transporter ATP-binding protein/permease; SP_2076, pseudogene; SP_2077, transcriptional regulator of arginine metabolism ArgR1; SP_2078, arginyl-tRNA synthetase gene argRS. (B) RT-PCR analysis of argR2 expression in TIGR4 and D39. Random primers were used to amplify cDNA. Genomic DNA was used as a positive control, and RNA was used as a negative control. (C) Immunoblot analysis of ArcA, ArcB, ArcC, ArgR2, ArgR1, and AhrC synthesis in nonencapsulated pneumococcal strains (TIGR4Δcps and D39Δcps) and isogenic regulatory mutants with bacterial whole-cell cytoplasmic protein lysates. Proteins were detected with specific mouse anti-ArcA, ArcB, ArcC, ArgR2, ArgR1, or AhrC antiserum. Pneumococcal enolase was used as a loading control. The predicted molecular masses are as follows: mature ArcA in TIGR4, 46.6 kDa; fragmented ArcA′ in D39, 28.3 kDa; ArcB, 37.9 kDa; ArcC, 33.6 kDa; ArgR2, 17.8 kDa; ArgR1, 16.2 kDa; AhrC, 17.1 kDa. WT, wild type. (D) Interaction of ArgR2 with putative promoter regions of the arc operon. Purified recombinant His-ArgR2 (0.5 to 8 pmol of protein) was incubated with the 437-bp arcA promoter fragment (EMSA_A), the 391-bp arcD promoter fragment (EMSA_D), or the 307-bp enolase promoter fragment (EMSA_E, negative control; DNA, 0.2 pmol).