Insensitivity of Chromosome I and the Cell Cycle to Blockage of Replication and Segregation of <named-content content-type="genus-species">Vibrio cholerae</named-content> Chromosome II

ABSTRACT Vibrio cholerae has two chromosomes (chrI and chrII) whose replication and segregation are under different genetic controls. The region covering the replication origin of chrI resembles that of the Escherichia coli chromosome, and both origins are under control of the highly conserved initi...

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Autores principales:	Ryosuke Kadoya, Dhruba K. Chattoraj
Formato:	article
Lenguaje:	EN
Publicado:	American Society for Microbiology 2012
Materias:	Microbiology QR1-502
Acceso en línea:	https://doaj.org/article/85e98c92db78453bae8bc60a9fb6648d
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spelling	oai:doaj.org-article:85e98c92db78453bae8bc60a9fb6648d2021-11-15T15:39:02ZInsensitivity of Chromosome I and the Cell Cycle to Blockage of Replication and Segregation of <named-content content-type="genus-species">Vibrio cholerae</named-content> Chromosome II10.1128/mBio.00067-122150-7511https://doaj.org/article/85e98c92db78453bae8bc60a9fb6648d2012-07-01T00:00:00Zhttps://journals.asm.org/doi/10.1128/mBio.00067-12https://doaj.org/toc/2150-7511ABSTRACT Vibrio cholerae has two chromosomes (chrI and chrII) whose replication and segregation are under different genetic controls. The region covering the replication origin of chrI resembles that of the Escherichia coli chromosome, and both origins are under control of the highly conserved initiator, DnaA. The origin region of chrII resembles that of plasmids that have iterated initiator-binding sites (iterons) and is under control of the chrII-specific initiator, RctB. Both chrI and chrII encode chromosome-specific orthologs of plasmid partitioning proteins, ParA and ParB. Here, we have interfered with chrII replication, segregation, or both, using extra copies of sites that titrate RctB or ParB. Under these conditions, replication and segregation of chrI remain unaffected for at least 1 cell cycle. In this respect, chrI behaves similarly to the E. coli chromosome when plasmid maintenance is disturbed in the same cell. Apparently, no checkpoint exists to block cell division before the crippled chromosome is lost by a failure to replicate or to segregate. Whether blocking chrI replication can affect chrII replication remains to be tested. IMPORTANCE Chromosome replication, chromosome segregation, and cell division are the three main events of the cell cycle. They occur in an orderly fashion once per cell cycle. How the sequence of events is controlled is only beginning to be answered in bacteria. The finding of bacteria that possess more than one chromosome raises the important question: how are different chromosomes coordinated in their replication and segregation? It appears that in the evolution of the two-chromosome genome of V. cholerae, either the secondary chromosome adapted to the main chromosome to ensure its maintenance or it is maintained independently, as are bacterial plasmids. An understanding of chromosome coordination is expected to bear on the evolutionary process of chromosome acquisition and on the efficacy of possible strategies for selective elimination of a pathogen by targeting a specific chromosome.Ryosuke KadoyaDhruba K. ChattorajAmerican Society for MicrobiologyarticleMicrobiologyQR1-502ENmBio, Vol 3, Iss 3 (2012)
institution	DOAJ
collection	DOAJ
language	EN
topic	Microbiology QR1-502
spellingShingle	Microbiology QR1-502 Ryosuke Kadoya Dhruba K. Chattoraj Insensitivity of Chromosome I and the Cell Cycle to Blockage of Replication and Segregation of <named-content content-type="genus-species">Vibrio cholerae</named-content> Chromosome II
description	ABSTRACT Vibrio cholerae has two chromosomes (chrI and chrII) whose replication and segregation are under different genetic controls. The region covering the replication origin of chrI resembles that of the Escherichia coli chromosome, and both origins are under control of the highly conserved initiator, DnaA. The origin region of chrII resembles that of plasmids that have iterated initiator-binding sites (iterons) and is under control of the chrII-specific initiator, RctB. Both chrI and chrII encode chromosome-specific orthologs of plasmid partitioning proteins, ParA and ParB. Here, we have interfered with chrII replication, segregation, or both, using extra copies of sites that titrate RctB or ParB. Under these conditions, replication and segregation of chrI remain unaffected for at least 1 cell cycle. In this respect, chrI behaves similarly to the E. coli chromosome when plasmid maintenance is disturbed in the same cell. Apparently, no checkpoint exists to block cell division before the crippled chromosome is lost by a failure to replicate or to segregate. Whether blocking chrI replication can affect chrII replication remains to be tested. IMPORTANCE Chromosome replication, chromosome segregation, and cell division are the three main events of the cell cycle. They occur in an orderly fashion once per cell cycle. How the sequence of events is controlled is only beginning to be answered in bacteria. The finding of bacteria that possess more than one chromosome raises the important question: how are different chromosomes coordinated in their replication and segregation? It appears that in the evolution of the two-chromosome genome of V. cholerae, either the secondary chromosome adapted to the main chromosome to ensure its maintenance or it is maintained independently, as are bacterial plasmids. An understanding of chromosome coordination is expected to bear on the evolutionary process of chromosome acquisition and on the efficacy of possible strategies for selective elimination of a pathogen by targeting a specific chromosome.
format	article
author	Ryosuke Kadoya Dhruba K. Chattoraj
author_facet	Ryosuke Kadoya Dhruba K. Chattoraj
author_sort	Ryosuke Kadoya
title	Insensitivity of Chromosome I and the Cell Cycle to Blockage of Replication and Segregation of <named-content content-type="genus-species">Vibrio cholerae</named-content> Chromosome II
title_short	Insensitivity of Chromosome I and the Cell Cycle to Blockage of Replication and Segregation of <named-content content-type="genus-species">Vibrio cholerae</named-content> Chromosome II
title_full	Insensitivity of Chromosome I and the Cell Cycle to Blockage of Replication and Segregation of <named-content content-type="genus-species">Vibrio cholerae</named-content> Chromosome II
title_fullStr	Insensitivity of Chromosome I and the Cell Cycle to Blockage of Replication and Segregation of <named-content content-type="genus-species">Vibrio cholerae</named-content> Chromosome II
title_full_unstemmed	Insensitivity of Chromosome I and the Cell Cycle to Blockage of Replication and Segregation of <named-content content-type="genus-species">Vibrio cholerae</named-content> Chromosome II
title_sort	insensitivity of chromosome i and the cell cycle to blockage of replication and segregation of <named-content content-type="genus-species">vibrio cholerae</named-content> chromosome ii
publisher	American Society for Microbiology
publishDate	2012
url	https://doaj.org/article/85e98c92db78453bae8bc60a9fb6648d
work_keys_str_mv	AT ryosukekadoya insensitivityofchromosomeiandthecellcycletoblockageofreplicationandsegregationofnamedcontentcontenttypegenusspeciesvibriocholeraenamedcontentchromosomeii AT dhrubakchattoraj insensitivityofchromosomeiandthecellcycletoblockageofreplicationandsegregationofnamedcontentcontenttypegenusspeciesvibriocholeraenamedcontentchromosomeii
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Insensitivity of Chromosome I and the Cell Cycle to Blockage of Replication and Segregation of <named-content content-type="genus-species">Vibrio cholerae</named-content> Chromosome II

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