Regulation of transcription of the repA1 gene in the replication control region of IncFII plasmid NR1 by gene dosage of the repA2 transcription repressor protein.

Journal Article (Journal Article)

Transcription of the repA1 gene of the IncFII plasmid NR1 is initiated at two promoters in the replication control region. Transcription from the upstream promoter is constitutive at a low level, whereas transcription from the downstream promoter is regulated. The 5' end of the constitutively synthesized transcript also encodes the transcription repressor protein for the regulated downstream promoter. Therefore, the level of the repressor protein in the cell is gene dosage dependent. Using both lac gene fusions and quantitative hybridization methods, we have determined the in vivo relationship between the rate of transcription from the regulated promoter and the repressor protein concentration as a function of gene dosage. At the wild-type copy number of NR1, transcription from the regulated promoter is 96% repressed, but substantial derepression occurs when the copy number falls below the normal value. At or above the normal plasmid copy number, the basal level of repA1 mRNA is provided by transcription from the constitutive upstream promoter.

Full Text

Duke Authors

Cited Authors

  • Dong, X; Womble, DD; Luckow, VA; Rownd, RH

Published Date

  • February 1985

Published In

Volume / Issue

  • 161 / 2

Start / End Page

  • 544 - 551

PubMed ID

  • 3155722

Pubmed Central ID

  • PMC214916

Electronic International Standard Serial Number (EISSN)

  • 1098-5530

International Standard Serial Number (ISSN)

  • 0021-9193

Digital Object Identifier (DOI)

  • 10.1128/jb.161.2.544-551.1985


  • eng