Emmanuelle Le Chatelier Jannière | Institut National de la Recherche Agronomique (original) (raw)

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Papers by Emmanuelle Le Chatelier Jannière

Research paper thumbnail of From metabolic hyperstructures to DNA replication complexes and back again

But technology will ultimately and usefully be better served by following the spirit of Eddington... more But technology will ultimately and usefully be better served by following the spirit of Eddington, by attempting to provide enough time and intellectual space for those who want to invest themselves in exploration of levels beyond the genome independently of any quick promises for still quicker solutions to extremely complex problems."

Research paper thumbnail of Countertranscript-driven attenuation system of the pAM?1 repE gene

Molecular Microbiology, 1996

The plasmid-encoded RepE protein is absolutely essential and rate-limiting for replication of the... more The plasmid-encoded RepE protein is absolutely essential and rate-limiting for replication of the promiscuous plasmid pAMβ1 originating from Enterococcus faecalis. We previously showed that the rep gene is transcribed from a promoter that is negatively regulated (10-fold reduction) by the CopF repressor. In this report, we show that this transcription is decreased a further 10-times by a countertranscript-driven transcriptional attenuation system. Extensive mutagenesis revealed that this system operates by a mechanism similar to that previously described for the unrelated repC gene of plasmid pT181.

Research paper thumbnail of The pAM?1 CopF repressor regulates plasmid copy number by controlling transcription of the repE gene

Molecular Microbiology, 1994

pAMβ1 is a low-copy-number, promiscuous plasmid from Gram-positive bacteria that replicates by a ... more pAMβ1 is a low-copy-number, promiscuous plasmid from Gram-positive bacteria that replicates by a unidirectional theta-type mode. Its replication is initiated by an original mechanism, involving the positive rate-limiting RepE protein. Here we show that the pAMβ1-encoded CopF protein is involved in negative regulation of the plasmid copy number. CopF represses -10-fold the transcription initiated at the promoter of the repE gene and binds to a 31 bp segment which is located immediately upstream of the -35 box of the repE promoter. We propose that CopF inhibits initiation of transcription at the repE promoter by binding to its operator.

Research paper thumbnail of A Fourth Class of Theta-Replicating Plasmids: The pAMbeta1 Family from Gram-Positive Bacteria

Proceedings of The National Academy of Sciences, 1993

Plasmid pAMfil from Enterococcus faecalis uses a unidirectional theta mode of replication. We sho... more Plasmid pAMfil from Enterococcus faecalis uses a unidirectional theta mode of replication. We show here that this replication (i) is dependent on a plasmid-encoded replication protein (Rep) but not on a DNA structure typical for origins of most Rep-dependent plasmids and (ii) is initiated by DNA polymerase I (PolI). pAMI31 minimal replicon shares no homology with highly conserved ColEl-type replicons, which use Poll for initiation but do not encode a Rep, or with CoIE2 and CoIE3 replicons, which require Poll for replication and encode a Rep. We propose that pAM,B1 and a number of other naturally occurring and closely related plasmids form a distinct plasmid class.

Research paper thumbnail of Genetic Evidence for a Link Between Glycolysis and DNA Replication

PLOS One, 2007

Background. A challenging goal in biology is to understand how the principal cellular functions a... more Background. A challenging goal in biology is to understand how the principal cellular functions are integrated so that cells achieve viability and optimal fitness in a wide range of nutritional conditions. Methodology/Principal Findings. We report here a tight link between glycolysis and DNA synthesis. The link, discovered during an analysis of suppressors of thermosensitive replication mutants in bacterium Bacillus subtilis, is very strong as some metabolic alterations fully restore viability to replication mutants in which a lethal arrest of DNA synthesis otherwise occurs at a high, restrictive, temperature. Full restoration of viability by such alterations was limited to cells with mutations in three elongation factors (the lagging strand DnaE polymerase, the primase and the helicase) out of a large set of thermosensitive mutants affected in most of the replication proteins. Restoration of viability resulted, at least in part, from maintenance of replication protein activity at high temperature. Physiological studies suggested that this restoration depended on the activity of the three-carbon part of the glycolysis/gluconeogenesis pathway and occurred in both glycolytic and gluconeogenic regimens. Restoration took place abruptly over a narrow range of expression of genes in the three-carbon part of glycolysis. However, the absolute value of this range varied greatly with the allele in question. Finally, restoration of cell viability did not appear to be the result of a decrease in growth rate or an induction of major stress responses. Conclusions/Significance. Our findings provide the first evidence for a genetic system that connects DNA chain elongation to glycolysis. Its role may be to modulate some aspect of DNA synthesis in response to the energy provided by the environment and the underlying mechanism is discussed. It is proposed that related systems are ubiquitous.

Research paper thumbnail of Genetic Evidence for a Link Between Glycolysis and DNA Replication

PLOS One, 2007

Background. A challenging goal in biology is to understand how the principal cellular functions a... more Background. A challenging goal in biology is to understand how the principal cellular functions are integrated so that cells achieve viability and optimal fitness in a wide range of nutritional conditions. Methodology/Principal Findings. We report here a tight link between glycolysis and DNA synthesis. The link, discovered during an analysis of suppressors of thermosensitive replication mutants in bacterium Bacillus subtilis, is very strong as some metabolic alterations fully restore viability to replication mutants in which a lethal arrest of DNA synthesis otherwise occurs at a high, restrictive, temperature. Full restoration of viability by such alterations was limited to cells with mutations in three elongation factors (the lagging strand DnaE polymerase, the primase and the helicase) out of a large set of thermosensitive mutants affected in most of the replication proteins. Restoration of viability resulted, at least in part, from maintenance of replication protein activity at high temperature. Physiological studies suggested that this restoration depended on the activity of the three-carbon part of the glycolysis/gluconeogenesis pathway and occurred in both glycolytic and gluconeogenic regimens. Restoration took place abruptly over a narrow range of expression of genes in the three-carbon part of glycolysis. However, the absolute value of this range varied greatly with the allele in question. Finally, restoration of cell viability did not appear to be the result of a decrease in growth rate or an induction of major stress responses. Conclusions/Significance. Our findings provide the first evidence for a genetic system that connects DNA chain elongation to glycolysis. Its role may be to modulate some aspect of DNA synthesis in response to the energy provided by the environment and the underlying mechanism is discussed. It is proposed that related systems are ubiquitous.

Research paper thumbnail of From metabolic hyperstructures to DNA replication complexes and back again

But technology will ultimately and usefully be better served by following the spirit of Eddington... more But technology will ultimately and usefully be better served by following the spirit of Eddington, by attempting to provide enough time and intellectual space for those who want to invest themselves in exploration of levels beyond the genome independently of any quick promises for still quicker solutions to extremely complex problems."

Research paper thumbnail of Countertranscript-driven attenuation system of the pAM?1 repE gene

Molecular Microbiology, 1996

The plasmid-encoded RepE protein is absolutely essential and rate-limiting for replication of the... more The plasmid-encoded RepE protein is absolutely essential and rate-limiting for replication of the promiscuous plasmid pAMβ1 originating from Enterococcus faecalis. We previously showed that the rep gene is transcribed from a promoter that is negatively regulated (10-fold reduction) by the CopF repressor. In this report, we show that this transcription is decreased a further 10-times by a countertranscript-driven transcriptional attenuation system. Extensive mutagenesis revealed that this system operates by a mechanism similar to that previously described for the unrelated repC gene of plasmid pT181.

Research paper thumbnail of The pAM?1 CopF repressor regulates plasmid copy number by controlling transcription of the repE gene

Molecular Microbiology, 1994

pAMβ1 is a low-copy-number, promiscuous plasmid from Gram-positive bacteria that replicates by a ... more pAMβ1 is a low-copy-number, promiscuous plasmid from Gram-positive bacteria that replicates by a unidirectional theta-type mode. Its replication is initiated by an original mechanism, involving the positive rate-limiting RepE protein. Here we show that the pAMβ1-encoded CopF protein is involved in negative regulation of the plasmid copy number. CopF represses -10-fold the transcription initiated at the promoter of the repE gene and binds to a 31 bp segment which is located immediately upstream of the -35 box of the repE promoter. We propose that CopF inhibits initiation of transcription at the repE promoter by binding to its operator.

Research paper thumbnail of A Fourth Class of Theta-Replicating Plasmids: The pAMbeta1 Family from Gram-Positive Bacteria

Proceedings of The National Academy of Sciences, 1993

Plasmid pAMfil from Enterococcus faecalis uses a unidirectional theta mode of replication. We sho... more Plasmid pAMfil from Enterococcus faecalis uses a unidirectional theta mode of replication. We show here that this replication (i) is dependent on a plasmid-encoded replication protein (Rep) but not on a DNA structure typical for origins of most Rep-dependent plasmids and (ii) is initiated by DNA polymerase I (PolI). pAMI31 minimal replicon shares no homology with highly conserved ColEl-type replicons, which use Poll for initiation but do not encode a Rep, or with CoIE2 and CoIE3 replicons, which require Poll for replication and encode a Rep. We propose that pAM,B1 and a number of other naturally occurring and closely related plasmids form a distinct plasmid class.

Research paper thumbnail of Genetic Evidence for a Link Between Glycolysis and DNA Replication

PLOS One, 2007

Background. A challenging goal in biology is to understand how the principal cellular functions a... more Background. A challenging goal in biology is to understand how the principal cellular functions are integrated so that cells achieve viability and optimal fitness in a wide range of nutritional conditions. Methodology/Principal Findings. We report here a tight link between glycolysis and DNA synthesis. The link, discovered during an analysis of suppressors of thermosensitive replication mutants in bacterium Bacillus subtilis, is very strong as some metabolic alterations fully restore viability to replication mutants in which a lethal arrest of DNA synthesis otherwise occurs at a high, restrictive, temperature. Full restoration of viability by such alterations was limited to cells with mutations in three elongation factors (the lagging strand DnaE polymerase, the primase and the helicase) out of a large set of thermosensitive mutants affected in most of the replication proteins. Restoration of viability resulted, at least in part, from maintenance of replication protein activity at high temperature. Physiological studies suggested that this restoration depended on the activity of the three-carbon part of the glycolysis/gluconeogenesis pathway and occurred in both glycolytic and gluconeogenic regimens. Restoration took place abruptly over a narrow range of expression of genes in the three-carbon part of glycolysis. However, the absolute value of this range varied greatly with the allele in question. Finally, restoration of cell viability did not appear to be the result of a decrease in growth rate or an induction of major stress responses. Conclusions/Significance. Our findings provide the first evidence for a genetic system that connects DNA chain elongation to glycolysis. Its role may be to modulate some aspect of DNA synthesis in response to the energy provided by the environment and the underlying mechanism is discussed. It is proposed that related systems are ubiquitous.

Research paper thumbnail of Genetic Evidence for a Link Between Glycolysis and DNA Replication

PLOS One, 2007

Background. A challenging goal in biology is to understand how the principal cellular functions a... more Background. A challenging goal in biology is to understand how the principal cellular functions are integrated so that cells achieve viability and optimal fitness in a wide range of nutritional conditions. Methodology/Principal Findings. We report here a tight link between glycolysis and DNA synthesis. The link, discovered during an analysis of suppressors of thermosensitive replication mutants in bacterium Bacillus subtilis, is very strong as some metabolic alterations fully restore viability to replication mutants in which a lethal arrest of DNA synthesis otherwise occurs at a high, restrictive, temperature. Full restoration of viability by such alterations was limited to cells with mutations in three elongation factors (the lagging strand DnaE polymerase, the primase and the helicase) out of a large set of thermosensitive mutants affected in most of the replication proteins. Restoration of viability resulted, at least in part, from maintenance of replication protein activity at high temperature. Physiological studies suggested that this restoration depended on the activity of the three-carbon part of the glycolysis/gluconeogenesis pathway and occurred in both glycolytic and gluconeogenic regimens. Restoration took place abruptly over a narrow range of expression of genes in the three-carbon part of glycolysis. However, the absolute value of this range varied greatly with the allele in question. Finally, restoration of cell viability did not appear to be the result of a decrease in growth rate or an induction of major stress responses. Conclusions/Significance. Our findings provide the first evidence for a genetic system that connects DNA chain elongation to glycolysis. Its role may be to modulate some aspect of DNA synthesis in response to the energy provided by the environment and the underlying mechanism is discussed. It is proposed that related systems are ubiquitous.