Molecular and General Genetics MGG

, Volume 209, Issue 1, pp 179–187

The functional stability of the lacZ transcript is sensitive towards sequence alterations immediately downstream of the ribosome binding site

  • Carsten Petersen

DOI: 10.1007/BF00329856

Cite this article as:
Petersen, C. Mol Gen Genet (1987) 209: 179. doi:10.1007/BF00329856


Various synthetic DNA sequences were inserted downstream of the fourth codon of the Escherichia coli lacZ gene on plasmids containing a hybrid lacZ-galK operon. Several different sequences, one as short as 10 bp, reduced the functional stability of the lacZ message three- to fourfold, whereas others had little or no effect. Introduction of synthetic sequences into a plasmid containing the intact lac operon resulted in similar reductions of mRNA stability. The sequence alterations also reduced the translational efficiency and transcription through lacZ as monitored by measurements of galactokinase synthesis from the downstream galK gene. There was no correlation between the average translational frequency and the stability of the lacZ message indicating that some of the inserted sequences reduced mRNA stability directly and not as a consequence of their effect on translation. The reduction of transcription through the lacZ gene correlated with the reduction of translation in agreement with current models of transcriptional polarity.

Key words

galK lacZ mRNA stability Transcriptional polarity Translational efficiency 


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Copyright information

© Springer-Verlag 1987

Authors and Affiliations

  • Carsten Petersen
    • 1
  1. 1.Institute of MicrobiologyUniversity of CopenhagenCopenhagen KDenmark

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