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  • 1
    Electronic Resource
    Electronic Resource
    The size of transcriptional units for ribosomal proteins in Escherichia coli (1974)
    Springer
    Molecular genetics and genomics 129 (1974), S. 11-26 
    Details
    ISSN: 1617-4623
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary An analysis of the degree to which the 55 ribosomal protein genes are clustered in polycistronic transcriptional units in E. coli is presented. Three kinetic approaches were applied: a) The labeling kinetics of RNA at different times after addition of rifampicin to a culture of E. coli growing in glucose minimal medium was used to calculate the distribution of transcribing RNA polymerases over different size classes of mRNA operons. The average length of transcriptional units being transcribed at a given time is about 3300 base pairs. Less than 1% of mRNA synthesis originates from transcriptional units longer than 12000 base pairs and only about 10% from units longer than 7500 base pairs. From this the upper limit of the length of ribosomal protein operons can be estimated. b) The rate of ribosomal protein synthesis as a fraction of the rate of total protein synthesis (αr) was measured during the cessation of mRNA synthesis and its decay after rifampicin addition. αr appears to decrease from 0.125 to 0.09 indicating that probably most ribosomal protein transcriptional units are shorter than the average. c) The kinetics of the rates of synthesis of individual ribosomal proteins was analysed after the release of the inhibition by rifampicin in a partially rifampicin resistant strain at 40°C. The rates of synthesis for all of the 40 ribosomal proteins tested reach half their final values at times falling in the interval 1.4–3.5 min, though for the majority it was reached between 1.6–2.6 min. We conclude that in E. coli the ribosomal protein genes are not joined to one extraordinarily long transcriptional unit but rather that there exist several small transcriptional units comprising up to 10 ribosomal protein genes each and that there may be one larger unit containing as many as 20 cistrons.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00269262
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  • 2
    Electronic Resource
    Electronic Resource
    Synthesis of ribosomal protein during the cell cycle of Escherichia coli B/r (1974)
    Springer
    Molecular genetics and genomics 129 (1974), S. 217-227 
    Details
    ISSN: 1617-4623
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The rate of synthesis of ribosomal protein relative to total protein synthesis (α r ) was found to vary during the cell cycle of Escherichia coli B/r. It is greater than the average value in newly arisen daughter cells and below average, when cells near division. The increase of α r follows the initiation of chromosome replication and can be understood as a consequence of the duplication of ribosomal protein genes, since many of them are clustered relatively close to the origin of replication. The variations of α r are being compared with the relative rate of fully induced β-galactosidase synthesis (α lac ) over the cell cycle, and possible constitutivity of ribosomal protein genes as proposed by Maaløe (1969) is discussed. If the ribosomal efficiency is constant during the cell cycle, the observed variation of α r implies that the increase in total protein deviates from an exponent by 3% over the cell cycle of E. coli B/r growing in glycerol medium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00267914
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  • 3
    Electronic Resource
    Electronic Resource
    Function of ribonuclease H in initiation of DNA replication in Escherichia coli K-12 (1985)
    Springer
    Molecular genetics and genomics 200 (1985), S. 103-109 
    Details
    ISSN: 1617-4623
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Escherichia coli rnh mutants lacking ribonuclease H (RNase H) activity can tolerate deletion of the origin of DNA Replication (ΔoriC) and transposon-insertional inactivation of an initiator gene (dnaA:Tn10). Introduction of the recA200 allele encoding a thermolabile RecA protein intornh − dnaA: Tn10 and rnh − ΔoriC mutants strains rendered DNA synthesis and colony formation of these mutants temperature sensitive. The temperature sensitivity and the broth sensitivity (Srm−) of the rnh − dnaA: Tn10 recA200 strain was suppressed by the presenceof plasmids (pBR322 derivatives) carrying dnaA +only when the intact oriC site was present on the chromosome. Lack of RNase H activity neither promoted replication of minichromosomes (pOC24 and pλasn20) in the absence of required DnaA+ protein nor inhibited dnaA +−dependent minichromosome replication. These results led to the conclusion that RNase H is not directly involved in the events leading to initiation of DNA replication at oriC. Rather, it functions as a specificity factor by eliminating certain forms of RNA-DNA hybrids which could otherwise be used to prime DNA replication at sites other than oriC.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00383320
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  • 4
    Electronic Resource
    Electronic Resource
    Origin of replication, oriC, of the Escherichia coli chromosome on specialized transducing phages λasn (1978)
    Springer
    Molecular genetics and genomics 160 (1978), S. 287-295 
    Details
    ISSN: 1617-4623
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Specialized transducing phages λasn harboring chromosomal DNA and genetic markers on either side of the asn gene were isolated. Phages carrying chromosomal DNA counterclockwise of the asn gene can upon infection establish themselves as self-replicating plasmids in asn, recA hosts lysogenic for lambda. It is concluded that this bypassing of normal lambda immunity is due to the presence of the chromosomal replication origin, oriC, in this class of phages. Genetic analysis and the determination of restriction endonuclease cleavage patterns of the different λasn lead to the allocation of oriC within 1.5 megadaltons of the asn gene towards the uncA, uncB genes at 82 min on the genetic map of E. coli, The clockwise order of genes on the chromosome is found to be: bglB, (pst, glmS), (uncA, uncB), criC, asn, trkD, rbs, rrnC, ilv.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00332972
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  • 5
    Electronic Resource
    Electronic Resource
    Interaction of alleles of therelA, relC andspoT genes inEscherichia coli: Analysis of the interconversion of GTP, ppGpp and pppGpp (1977)
    Springer
    Molecular genetics and genomics 150 (1977), S. 87-101 
    Details
    ISSN: 1617-4623
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Mutants in thespoT gene have been isolated as stringent second site revertants of therelC mutation. These show varying degrees of the characteristics associated with thespoT1 gene,viz relative amount and absolute levels of both pppGpp and ppGpp and the decay rate of the latter. The entry of3H-guanosine into GTP and ppGpp pools inspoT + andspoT1 cells either growing exponentially or during amino acid starvation was determined, and the rate of ppGpp synthesis and its decay constant calculated. During exponential growth the ppGpp pool is 2-fold higher, its decay constant 10-fold lower, and its synthesis rate 5-fold lower inspoT - than inspoT + cells; during amino acid starvation the ppGpp pool is 2-fold higher, its decay constant 20-fold lower, and its synthesis rate 10-fold lower inspoT than inspoT + cells. In one of the “intermediate”spoT mutants the rate of entry of3H-guanosine into GTP, ppGpp and pppGpp was measured during amino acid starvation. The data form the basis of a model for the interconversion of the guanosine nucleotides in which the flow is:GDP→GTP→pppGpp→ppGpp→Y. Calculations of the rates of synthesis and conversion of pppGpp and ppGpp under various conditions in variousspoT + andspoT - strains indicate that the ppGpp concentration indirectly controls the rate of pppGpp synthesis. ThespoT1 allele was introduced into various relaxed mutants. It was shown that many phenomena associated with the relaxed response ofrelC and “intermediate”relA mutants were phenotypically suppressed when thespoT1 allele was introduced into these mutants. These double mutants exhibit ppGpp accumulation, rate of RNA accumulation, rate of β-galactosidase synthesis, and heat lability of β-galactosidase synthesized during amino acid starvation similar to the stringent wild-type. It is concluded that the relaxed response is due directly to the lack of ppGpp and that the stringest response is due directly to ppGpp.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02425329
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  • 6
    Electronic Resource
    Electronic Resource
    Genetic and physical mapping of recF in Escherichia coli K-12 (1980)
    Springer
    Molecular genetics and genomics 180 (1980), S. 115-121 
    Details
    ISSN: 1617-4623
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Two factor transductional crosses place recF at approximately 82 min on the E. coli chromosome; recF is highly cotransducible with dnaA and gyrB (cou). Transductional analysis with a series of λtna specialized transducing phages carrying chromosomal DNA from the tnaA region place recF between dnaA and gyrB. This analysis also indicates that a gene lying in the same region and producing an easily detectable protein (estimated MW of 45 kD) is dnaN and not recF.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00267359
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  • 7
    Electronic Resource
    Electronic Resource
    The nucleotide sequence of the atp genes coding for the F0 subunits a, b, c and the F1 subunit δ of the membrane bound ATP synthase of Escherichia coli (1981)
    Springer
    Molecular genetics and genomics 184 (1981), S. 33-39 
    Details
    ISSN: 1617-4623
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The nucleotide sequence has been determined of a 2.500 base pair segment of the E. coli chromosome located between 3.75 and 6.25 kb counterclockwise of the origin of replication at 83.5 min. The sequence contains the atp genes coding for subunits a-, b-, c-, δ- and part of the α-subunit of the membrane bound ATP synthase. The precise start positions of the atpE (c), atpF (b), atpH (δ) and atpA (α) genes have been defined by comparison of the potential coding sequences with the known amino acid sequence of the c-subunit and the determined N-terminal amino acid sequences of the respective subunits. The genes are expressed in the counterclockwise direction. Their order (counterclockwise) is: atpB (a), atpE (c), atpF (b), atpH (δ) and atpA (α). The coding sequences for subunits b and δ yield polypeptides of 156 and 177 amino acids, respectively, in accordance with the established sizes of these subunits; the one for the c-subunit, the DCCD binding protein, fits perfectly with its known sequence of 79 amino acids. The a-subunit is comprised within a coding sequence yielding a polypeptide of 271 amino acids. It is suggested, however, that the a-subunit (atpB) contains only 201 amino acids, in accordance with its known size, starting from a translation initiation site within the larger coding sequence. The stoichiometry of the F0 sector subunits is discussed and a model is proposed for the functioning of the highly charged b-subunit of the F0 sector as the actual proton conductor.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00271191
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  • 8
    Electronic Resource
    Electronic Resource
    The size of transcriptional units for ribosomal proteins in Escherichia coli rates of synthesis of ribosomal proteins during a nutritional shift-up (1974)
    Springer
    Molecular genetics and genomics 130 (1974), S. 271-274 
    Details
    ISSN: 1617-4623
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The kinetics of the rate of synthesis of the ribosomal proteins has been determined during a nutritional shift-up in E. coli. Evidence is obtained for a maximal transcription time of 2 min for possible transcriptional units for ribosomal proteins. This is in accordance with the earlier conclusion that ribosomal protein genes are clustered in several relatively small transcriptional units (Molin et al., 1974).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00268805
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  • 9
    Electronic Resource
    Electronic Resource
    A ribosomal RNA gene, rrnC, of Escherichia coli, mapped by specialized transducing λdilv and λdrbs phages (1978)
    Springer
    Molecular genetics and genomics 163 (1978), S. 223-228 
    Details
    ISSN: 1617-4623
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Specialized transducing phages carrying segments of the Escherichia coli chromosome from the rbs-ilv region including rrn genes have been isolated. These phages carry rrn transcription units coding for 16S and 23S rRNA with the direction of transcription clockwise towards the ilv operon. While one of the phages (λd279rbs) appears to carry the genuine rrn gene, denoted rrnC, located between rbs and ilv at 82 min on the E. coli chromosome another one isolated as an ilv transducing phage, λd5ilv, carries a hybrid rrn gene, denoted rrnX, which has originated from a recombinational cross-over between the rrnC and one of the other rrn genes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00267413
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  • 10
    Electronic Resource
    Electronic Resource
    The genes for the eight subunits of the membrane bound ATP synthase of Escherichia coli (1981)
    Springer
    Molecular genetics and genomics 183 (1981), S. 463-472 
    Details
    ISSN: 1617-4623
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The genes for the eight subunits of the membrane bound ATP synthase of Escherichia coli (Ca++, Mg++ dependent ATPase, EC 3.6.1.3) were mapped through genetic, physical and functional analysis of specialized transducing phages λasn (von Meyenburg et al. 1978). The ATP synthase genes, designated atp 1, are located at 83.2 min in a segment of the chromosome between 3.5 and 11.3 kb left (counterclockwise) of the origin of replication oriC. The counterclockwise order of the genes for the eight subunits, the expression of which starts from a control region at 3.5 kb-L, was found to be: a, (c, b, δ), α, γ, (ε, β) which in the notation of Downie et al. (1981) reads atpB (E F H) A G (C D). The analysis was in part based on the isolation of new types of atp (unc, Suc-) mutations. We made use of the fact that specialized transducing phages λasn carrying oriC can establish themselves as minichromosomes rendering asnA cells Asn+, and that the resulting Asn+ cells grow slowly if the λasn carries part or all of the atp operon. Selecting for fast growing strains mutations were isolated on the λasn which either eliminated atp genes or affected their expression (“promoter” mutations). The relationship between these atp mutations and the cop mutations of Ogura et al. (1980), which also appear to map in front of or within the atp genes, is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00268766
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