Escherichia coli rep gene: identification of the promoter and N terminus of the rep protein

Abstract

The functional Escherichia coli rep gene, which encodes the M, 67,000 Rep helicase, has been localized within a 2.55-kilobase sequence. Its regulatory region has been characterized by the use of rep-lacZ fusions. The direction of transcription of the rep gene is clockwise on the E. coli chromosome, as are the nearby ilvC and rho genes. The sequence of the rep control region was determined, and putative regulatory sequences were identified; no evidence for autoregulation of expression was obtained. Transcription of the gene was not enhanced during the SOS response. The location of the promoter and the beginning of the protein were confirmed by S1 nuclease mapping of the 5' end of rep mRNA and determination of the NH2-terminal sequence of the rep protein. * Corresponding author. t This is the paper no. 8 in a series on the rep mutation. The previous paper is reference 4.

Escherichia coli repgene: sequence of the gene, the encoded helicase, and its homology withuvrD*

“…The slightly larger 310-bp Sau3AI fragment was isolated, 3' end labelled as above, cut with HindII and the resulting 268-bp Sau3AI-HindII fragment isolated and hybridized to RNA from E. coli MZ-1 transformed with pRepO, a plasmid expressing the rep gene at high levels (J. Colasanti unpublished). Si nuclease digestions were performed as described in (16). The protected fragments were electrophoresed alongside Sau3AI-cut pBR322.…”

“…In the case of rho it is not evident why the combination of mutations is lethal. In our laboratory the rep gene has been cloned and the rep promoter and N-terminal amino acid sequence identified (15,16). In this paper we present the complete sequence of a 2.67-kb region of the E. coli chromosome that contains the rep gene.…”

Genotyping of Staphylococcus epidermidis by Small‐Fragment Restriction Endonuclease Analysis and Pulsed‐Field Gel Electrophoresis of Genomic Restriction Fragments

“…Plasmid profiles have successfully been used as epidemiological markers by several workers (27), but they are known to be occasionally subject to alteration due to loss or dynamic intra-and interspecies transfer (3,9). In this study, the patterns of undigested plasmid DNAs were stable and gave evidence for the same interpretation as did the results of chromosome analysis.…”

“…In recent years coagulase-negative staphylococci, particularly Staphylococcus epidermidis, have emerged as important nosocomial pathogens (18,26,27). S. epidermidis has been reported to be the cause of a variety of clinically significant infections in elderly and immunocompromised patients and in neonates (3,7,16), most frequently associated with indwelling catheters (23), implanted devices and grafts (2), or severe underlying disease(15). Its role in causing prolonged hospital stay and elevated mortality has clearly been established in controlled studies (15,16,24).…”

“…Despite their significance, epidemiological ques-tions often remain unanswered because most classical typing systems readily available in routine microbiology laboratories are not suited to resolve the complex epidemiology of this species. Recent developments in DNA analysis techniques such as genome fingerprinting by restriction endonuclease analysis (3,4,31) and Southern hybridization (10, 30) have resulted in new methods that can be used for the genotypic characterization of S. epidermidis isolates. These techniques have successfully been employed for the epidemiological tracking of S. epidermidis and were demonstrated to be superior to conventional phenotypic typing methods (3,4,14,28,31).…”