ORCID Profile
0000-0002-2358-2344
Current Organisation
University of Oxford
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Publisher: Proceedings of the National Academy of Sciences
Date: 16-12-2013
Abstract: Proteins bound to DNA often interact with proteins bound elsewhere on the same DNA to regulate gene expression. The intervening DNA tethers the proteins near each other, making their interaction efficient and specific, but the importance of this tethering effect is poorly understood at large DNA separations. We quantitated tethering inside bacterial cells, using two different proteins at separations up to 10,000 bp, to show that tethering is strong enough to drive efficient interactions over these distances. The same interactions were ∼10-fold weaker outside cells, implying that cellular factors enhance tethering. However, tethering was lost at a DNA separation of 500,000 bp inside bacteria, indicating special mechanisms inside eukaryotic cells to provide efficient and specific interactions over such distances.
Publisher: Proceedings of the National Academy of Sciences
Date: 06-10-2014
Abstract: Genes are frequently regulated by interactions between proteins that bind to the DNA near the gene and proteins that bind to DNA sites located far away, with the intervening DNA looped out. In eukaryotic genomes, genes and their distant sites are intermingled in complex ways and it is not understood how the correct connections are formed. Using two pairs of DNA-looping sites in bacterial cells, we tested the idea that one DNA loop can either assist or interfere with the formation of another DNA loop. By measuring the strength of these interactions between loops, we showed that this mechanism is capable of directing a distant site to the correct gene and preventing it contacting the wrong gene.
Publisher: American Society for Microbiology
Date: 15-02-2019
DOI: 10.1128/JB.00545-18
Abstract: Escherichia coli infections can be a major health burden, especially with the organism becoming increasingly resistant to “last-resort” antibiotics such as carbapenems. Although colicins are potent narrow-spectrum antimicrobials with potential as future antibiotics, high levels of naturally occurring colicin insensitivity have been documented which could limit their efficacy. We identify O-antigen-dependent colicin insensitivity in a clinically relevant uropathogenic E. coli strain and show that this insensitivity can be circumvented by minor changes to growth conditions. The results of our study suggest that colicin insensitivity among E. coli organisms has been greatly overestimated, and as a consequence, colicins could in fact be effective species-specific antimicrobials targeting pathogenic E. coli such as uropathogenic E. coli (UPEC).
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Sandip Kumar.