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Expression and phase variation of gonococcal P.11 genes in Escherichia coli involves ribosomal frameshifting and slipped‐strand mispairing
Author(s) -
Belland R. J.,
Morrison S. G.,
Ley P.,
Swanson J.
Publication year - 1989
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.1989.tb00226.x
Subject(s) - biology , frameshift mutation , phase variation , escherichia coli , gene , genetics , coding region , stop codon , microbiology and biotechnology , mutation , virulence
Summary Expression and phase variation of Neisseria gonorr‐hoeae P.ll genes in Escherichia coli viere studied using TnphoA fusions. Fusions were created in the P.llc gene of N. gonorrhoeae JS3 using λ TnphoA‐ 1 and were characterized by restriction digestion and dideoxy sequencing. Three fusions were chosen for further study; Tnp7 (fusion junction at mature amino acid 7), Tnp57 (amino acid 57), Tnp66 (amino acid 66). All fusions were in frame with the P.llc coding sequence but were out of frame with the purported initiation codon. All fusion constructions were shown to phase vary in E. coli in an analogous fashion to that seen in N. gonorrhoeae , i.e. phase changes (in a recA background) at a frequency of c. 10 −3 accompanied by an alteration at the DNA level of the number of coding repeats (CRs). In vitro mutagenesis of the fusion constructions indicated that expression of out of frame P.ll genes in E. coli was probably the result of ribosomal frameshifting within the run of ‘A’ residues immediately preceding the CR region and not due to low‐level false initiation at codons other than the ATG initiation codon (as had previously been suggested). The mechanism for P.llc::phoA phase variation appears to be related to the ‘slipped‐strand mispairing’ mechanism responsible for frameshift mutations in a number of other bacterial genes containing short, direct, tandem repeats.