1. Molecular dissection of the replication system of plasmid pIGRK encoding two in-frame Rep proteins with antagonistic functions
- Author
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Anna Bierczyńska-Krzysik, Anna Mazurkiewicz-Pisarek, Andrzej Plucienniczak, Dariusz Bartosik, Paweł Wawrzyniak, Paulina Kabaj, Piotr Kierył, Natalia Łukasiewicz, Piotr Baran, Piotr Zaleski, Agata Gościk, and Agnieszka Sobolewska-Ruta more...
- Subjects
Microbiology (medical) ,lcsh:QR1-502 ,Replication Origin ,Locus (genetics) ,Biology ,Replication system ,Microbiology ,Genome ,lcsh:Microbiology ,In-frame proteins ,03 medical and health sciences ,chemistry.chemical_compound ,Overlapping genes ,Plasmid ,Bacterial Proteins ,Start codon ,Gene Duplication ,Gene duplication ,Cloning, Molecular ,Promoter Regions, Genetic ,Gene ,030304 developmental biology ,Genetics ,Regulation of gene expression ,0303 health sciences ,030306 microbiology ,Transcription regulation ,Gene Expression Regulation, Bacterial ,Rep protein ,DNA-Binding Proteins ,Klebsiella pneumoniae ,chemistry ,Protein Multimerization ,Plasmid replication ,DNA ,Research Article ,Plasmids - Abstract
BackgroundGene overlapping is a frequent phenomenon in microbial genomes. Excluding so-called “trivial overlapping”, there are significant implications of such genetic arrangements, including regulation of gene expression and modification of protein activity. It is also postulated that, besides gene duplication, the appearance of overlapping genes (OGs) is one of the most important factors promoting a genome’s novelty and evolution. OGs coding for in-frame proteins with different functions are a particularly interesting case. In this study we identified and characterized two in-frame proteins encoded by OGs on plasmid pIGRK fromKlebsiella pneumoniae, a representative of the newly distinguished pHW126 plasmid family.ResultsA singlerepRlocus located within the replication system of plasmid pIGRK encodes, in the same frame, two functional polypeptides: a full-length RepR protein and a RepR’ protein (withN-terminal truncation) translated from an internal START codon. Both proteins form homodimers, and interact with diverse DNA regions within the plasmid replication origin andrepRpromoter operator. Interestingly, RepR and RepR’ have opposing functions – RepR is crucial for initiation of pIGRK replication, while RepR’ is a negative regulator of this process. Nevertheless, both proteins act cooperatively as negative transcriptional regulators of their own expression.ConclusionsRegulation of the initiation of pIGRK replication is a complex process in which a major role is played by two in-frame proteins with antagonistic functions. In-frame encoded Rep proteins are uncommon, having been described in only a few plasmids. This is the first description of such proteins in a plasmid of the pHW126 family. more...
- Published
- 2019
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