Dataset Information

PclR is a transcriptional activator of the gene that encodes the pneumococcal collagen-like protein PclA.

ABSTRACT: The Gram-positive bacterium Streptococcus pneumoniae is a major human pathogen that shows high levels of genetic variability. The pneumococcal R6 genome harbours several gene clusters that are not present in all strains of the species. One of these clusters contains two divergent genes, pclA, which encodes a putative surface-exposed protein that contains large regions of collagen-like repeats, and spr1404 (here named pclR). PclA was shown to mediate pneumococcal adherence to host cells in vitro. In this work, we demonstrate that PclR (494 amino acids) is a transcriptional activator. It stimulates transcription of the pclA gene by binding to a specific DNA site upstream of the core promoter. In addition, we show that PclR has common features with the MgaSpn transcriptional regulator (493 amino acids), which is also encoded by the R6 genome. These proteins have high sequence similarity (60.3%), share the same organization of predicted functional domains, and generate multimeric complexes on linear double-stranded DNAs. However, on the PpclA promoter region, MgaSpn binds to a site different from the one recognized by PclR. Our results indicate that PclR and MgaSpn have similar DNA-binding properties but different DNA-binding specificities, pointing to a different regulatory role of both proteins.

SUBMITTER: Moreno-Blanco A

PROVIDER: S-EPMC9276737 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:On the basis of the constitutive phenotypes of two catM mutants of Acinetobacter calcoaceticus, the CatM protein was proposed to repress expression of two different loci involved in catechol degradation, catA and catBCIJFD (E. Neidle, C. Hartnett, and L. N. Ornston, J. Bacteriol. 171:5410-5421, 1989). In spite of its proposed negative role as a repressor, CatM is similar in amino acid sequence to positive transcriptional activators of the LysR family. Investigating this anomaly, we found that insertional inactivation of catM did not cause the phenotype expected for the disruption of a repressor-encoding gene: in an interposon-generated catM mutant, no cat genes were expressed constitutively, but rather catA and catB were still inducible by muconate. Moreover, this catM mutant grew poorly on benzoate, a process requiring the expression of all cat genes. The inducibility of the cat genes in this catM mutant was completely eliminated by a 3.5-kbp deletion 10 kbp upstream of catM. In this double mutant, catM in trans restored muconate inducibility to both catA and catB. These results suggested the presence of an additional regulatory locus controlling cat gene expression. The ability of CatM to function as an activator was also suggested by these results. In support of this hypothesis, in vivo methylation protection assays showed that CatM protects two guanines in a dyad 65 nucleotides upstream of the catB transcriptional start site, in a location and pattern typical of LysR-type transcriptional activators. Gel mobility shift assays indicated that CatM also binds to a region upstream of catA. DNA sequence analysis revealed a nucleotide near the 3' end of catM not present in the published sequence. Translation of the corrected sequence resulted in the deduced CatM protein being 52 residues longer than previously reported. The size, amino acid sequence, and mode of action of CatM now appear similar to, and typical of, what has been found for transcriptional activators in the LysR family. Analysis of one of the constitutive alleles of catM previously thought to encode a dysfunctional repressor indicated instead that it encodes an inducer-independent transcriptional activator.

Dataset Information

PclR is a transcriptional activator of the gene that encodes the pneumococcal collagen-like protein PclA.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets