Identification and sequence of gene dicB: translation of the division inhibitor from an in-phase internal start

Nucleic Acids Res. 1988 Jul 25;16(14A):6327-38. doi: 10.1093/nar/16.14.6327.


The dicA1 mutation, located in the replication termination region of Escherichia coli at 34.9 min, confers a temperature-sensitive, division defective phenotype to its hosts. Previous analysis had suggested that dicA codes for a repressor of a nearby division inhibition gene dicB. We show now that gene dicB is part of a complex operon. Five open reading frames (ORFs 1 to 5) preceeded by a promoter sensitive to dicA repression are found within a 1500 bp segment, and are organized into two clusters separated by a long untranslated region. Evidence for expression of these ORFs was obtained from in vitro or in vivo translation of plasmid-coded genes. IPTG-dependent cell filamentation was obtained when either the entire or the C-terminal part of the fourth ORF was placed under control of the lac promoter. In both cases, a 7 KD protein corresponding to translation from an in-frame ATG of ORF4 (dicB) was made. We propose that this C-terminal protein is the division inhibitor synthesized in dicA1 mutants.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • Cell Division*
  • Cloning, Molecular
  • Escherichia coli / genetics*
  • Genes, Bacterial*
  • Molecular Sequence Data
  • Operon
  • Plasmids
  • Transformation, Genetic

Associated data

  • GENBANK/X07465