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Charles C. Richardson - One of the best experts on this subject based on the ideXlab platform.

  • The thIoredoxIn bIndIng domaIn of bacterIophage T7 DNA Polymerase confers processIvIty on EscherIchIa colI DNA Polymerase I.
    Proceedings of the National Academy of Sciences of the United States of America, 1997
    Co-Authors: Ella Bedford, Stanley Tabor, Charles C. Richardson
    Abstract:

    BacterIophage T7 DNA Polymerase shares extensIve sequence homology wIth EscherIchIa colI DNA Polymerase I. However, In vIvo, E. colI DNA Polymerase I Is Involved prImarIly In the repaIr of DNA whereas T7 DNA Polymerase Is responsIble for the replIcatIon of the vIral genome. In accord wIth these roles, T7 DNA Polymerase Is hIghly processIve whIle E. colI DNA Polymerase I has low processIvIty. The hIgh processIvIty of T7 DNA Polymerase Is achIeved through tIght bIndIng to Its processIvIty factor, E. colI thIoredoxIn. We have IdentIfIed a unIque 76-resIdue domaIn In T7 DNA Polymerase responsIble for thIs InteractIon. InsertIon of thIs domaIn Into the homologous sIte In E. colI DNA Polymerase I results In a dramatIc Increase In the processIvIty of the chImerIc DNA Polymerase, a phenomenon that Is dependent upon Its bIndIng to thIoredoxIn.

Tokio Kogoma - One of the best experts on this subject based on the ideXlab platform.

  • DNA Polymerase I In constItutIve stable DNA replIcatIon In EscherIchIa colI.
    Journal of bacteriology, 1997
    Co-Authors: Tokio Kogoma, R R Maldonado
    Abstract:

    We examIned the effects of mutatIons In the polA (encodIng DNA Polymerase I) and polB (DNA Polymerase II) genes on InducIble and constItutIve stable DNA replIcatIon (ISDR and cSDR, respectIvely), the two alternatIve DNA replIcatIon systems of EscherIchIa colI. The polA25::mInITn10spc mutatIon severely InactIvated cSDR, whereas polA1 mutants exhIbIted a sIgnIfIcant extent of cSDR. cSDR requIred both the Polymerase and 5'-->3' exonuclease actIvItIes of DNA Polymerase I. A sImIlar requIrement for both actIvItIes was found In replIcatIon of the pBR322 plasmId In vIvo. DNA Polymerase II was requIred neIther for cSDR nor for ISDR. In addItIon, we found that the lethal combInatIon of an rnhA (RNase HI) and a polA mutatIon could be suppressed by the lexA(Def) mutatIon.

  • DNA Polymerase I and the bypassIng of RecA dependence of constItutIve stable DNA replIcatIon In EscherIchIa colI rnhA mutants.
    Journal of bacteriology, 1993
    Co-Authors: Yang Cao, R. R.r. Rowland, Tokio Kogoma
    Abstract:

    In EscherIchIa colI rnhA mutants, several normally repressed orIgIns (orIK sItes) of DNA replIcatIon are actIvated. The type of DNA replIcatIon InItIated from these orIgIns, termed constItutIve stable DNA replIcatIon, does not requIre DNAA proteIn or the orIC sIte, whIch are essentIal for normal DNA replIcatIon. It requIres actIve RecA proteIn. We prevIously found that the lexA71(Def)::Tn5 mutatIon can suppress thIs RecA requIrement and postulated that the derepressIon of a LexA regulon gene(s) leads to the actIvatIon of a bypass pathway, RIp (for RecA-Independent process). In thIs study, we Isolated a mInITn10spc InsertIon mutant that abolIshes the abIlIty of the lexA(Def) mutatIon to suppress the RecA requIrement of constItutIve stable DNA replIcatIon. ClonIng and DNA sequencIng analysIs of the mutant revealed that the InsertIon occurs at the 3' end of the codIng regIon of the polA gene, whIch encodes DNA Polymerase I. The mutant allele, desIgnated polA25::mInITn10spc, Is expected to abolIsh the polymerIzatIon actIvIty but not the 5'-->3' or 3'-->5' exonuclease actIvIty. Thus, the RIp bypass pathway requIres actIve DNA Polymerase I. SInce the lethal combInatIon of recA(Def) and polA25::mInITn10spc could be suppressed by derepressIon of the LexA regulon only when DNA replIcatIon Is drIven by the orIC system, It was suggested that the bypass pathway has a specIfIc requIrement for DNA Polymerase I at the InItIatIon step In the absence of RecA. An accompanyIng paper (Y. Cao and T. Kogoma, J. BacterIol. 175:7254-7259, 1993) descrIbes experIments to determIne whIch actIvItIes of DNA Polymerase I are requIred at the InItIatIon step and dIscusses possIble roles for DNA Polymerase In the RIp bypass pathway.

Ella Bedford - One of the best experts on this subject based on the ideXlab platform.

  • The thIoredoxIn bIndIng domaIn of bacterIophage T7 DNA Polymerase confers processIvIty on EscherIchIa colI DNA Polymerase I.
    Proceedings of the National Academy of Sciences of the United States of America, 1997
    Co-Authors: Ella Bedford, Stanley Tabor, Charles C. Richardson
    Abstract:

    BacterIophage T7 DNA Polymerase shares extensIve sequence homology wIth EscherIchIa colI DNA Polymerase I. However, In vIvo, E. colI DNA Polymerase I Is Involved prImarIly In the repaIr of DNA whereas T7 DNA Polymerase Is responsIble for the replIcatIon of the vIral genome. In accord wIth these roles, T7 DNA Polymerase Is hIghly processIve whIle E. colI DNA Polymerase I has low processIvIty. The hIgh processIvIty of T7 DNA Polymerase Is achIeved through tIght bIndIng to Its processIvIty factor, E. colI thIoredoxIn. We have IdentIfIed a unIque 76-resIdue domaIn In T7 DNA Polymerase responsIble for thIs InteractIon. InsertIon of thIs domaIn Into the homologous sIte In E. colI DNA Polymerase I results In a dramatIc Increase In the processIvIty of the chImerIc DNA Polymerase, a phenomenon that Is dependent upon Its bIndIng to thIoredoxIn.

Stanley Tabor - One of the best experts on this subject based on the ideXlab platform.

  • The thIoredoxIn bIndIng domaIn of bacterIophage T7 DNA Polymerase confers processIvIty on EscherIchIa colI DNA Polymerase I.
    Proceedings of the National Academy of Sciences of the United States of America, 1997
    Co-Authors: Ella Bedford, Stanley Tabor, Charles C. Richardson
    Abstract:

    BacterIophage T7 DNA Polymerase shares extensIve sequence homology wIth EscherIchIa colI DNA Polymerase I. However, In vIvo, E. colI DNA Polymerase I Is Involved prImarIly In the repaIr of DNA whereas T7 DNA Polymerase Is responsIble for the replIcatIon of the vIral genome. In accord wIth these roles, T7 DNA Polymerase Is hIghly processIve whIle E. colI DNA Polymerase I has low processIvIty. The hIgh processIvIty of T7 DNA Polymerase Is achIeved through tIght bIndIng to Its processIvIty factor, E. colI thIoredoxIn. We have IdentIfIed a unIque 76-resIdue domaIn In T7 DNA Polymerase responsIble for thIs InteractIon. InsertIon of thIs domaIn Into the homologous sIte In E. colI DNA Polymerase I results In a dramatIc Increase In the processIvIty of the chImerIc DNA Polymerase, a phenomenon that Is dependent upon Its bIndIng to thIoredoxIn.

Yang Cao - One of the best experts on this subject based on the ideXlab platform.

  • DNA Polymerase I and the bypassIng of RecA dependence of constItutIve stable DNA replIcatIon In EscherIchIa colI rnhA mutants.
    Journal of bacteriology, 1993
    Co-Authors: Yang Cao, R. R.r. Rowland, Tokio Kogoma
    Abstract:

    In EscherIchIa colI rnhA mutants, several normally repressed orIgIns (orIK sItes) of DNA replIcatIon are actIvated. The type of DNA replIcatIon InItIated from these orIgIns, termed constItutIve stable DNA replIcatIon, does not requIre DNAA proteIn or the orIC sIte, whIch are essentIal for normal DNA replIcatIon. It requIres actIve RecA proteIn. We prevIously found that the lexA71(Def)::Tn5 mutatIon can suppress thIs RecA requIrement and postulated that the derepressIon of a LexA regulon gene(s) leads to the actIvatIon of a bypass pathway, RIp (for RecA-Independent process). In thIs study, we Isolated a mInITn10spc InsertIon mutant that abolIshes the abIlIty of the lexA(Def) mutatIon to suppress the RecA requIrement of constItutIve stable DNA replIcatIon. ClonIng and DNA sequencIng analysIs of the mutant revealed that the InsertIon occurs at the 3' end of the codIng regIon of the polA gene, whIch encodes DNA Polymerase I. The mutant allele, desIgnated polA25::mInITn10spc, Is expected to abolIsh the polymerIzatIon actIvIty but not the 5'-->3' or 3'-->5' exonuclease actIvIty. Thus, the RIp bypass pathway requIres actIve DNA Polymerase I. SInce the lethal combInatIon of recA(Def) and polA25::mInITn10spc could be suppressed by derepressIon of the LexA regulon only when DNA replIcatIon Is drIven by the orIC system, It was suggested that the bypass pathway has a specIfIc requIrement for DNA Polymerase I at the InItIatIon step In the absence of RecA. An accompanyIng paper (Y. Cao and T. Kogoma, J. BacterIol. 175:7254-7259, 1993) descrIbes experIments to determIne whIch actIvItIes of DNA Polymerase I are requIred at the InItIatIon step and dIscusses possIble roles for DNA Polymerase In the RIp bypass pathway.