Suppression of TGA Mutations in the Bacillus subtilis spoIIR Gene by prfB Mutations

AUTOR(ES)

Karow, Margaret L.

FONTE

American Society for Microbiology

RESUMO

An unexpectedly high proportion of TGA nonsense mutations was obtained in a collection of chemically induced mutations in the spoIIR locus of Bacillus subtilis. Of 11 different mutations obtained, TGA mutations were found in four codons, whereas only three codons yielded missense mutations. Six suppressors of the TGA mutations were isolated, and five of the suppressing mutations were mapped to the prfB gene encoding protein release factor 2. These are the first mutations shown to map to the B. subtilis prfB locus. The sequence of the prfB gene was completed, and two revisions of the published sequence were made. The five prfB mutations also resulted in suppression of the catA86-TGA mutation to between 19 and 54% of the expression of catA86+, compared to the readthrough level of 6% in the prfB+ strain. N-terminal sequencing of suppressed catA86-TGA-specified protein demonstrated that the amino acid inserted at UGA because of the prfB1 mutations was tryptophan.

Documentos Relacionados

• The Chromosomal Location of the Bacillus subtilis Sporulation Gene spoIIR Is Important for Its Function
• Identification of a gene, spoIIR, that links the activation of sigma E to the transcriptional activity of sigma F during sporulation in Bacillus subtilis.
• Conditionally lethal and recessive UGA-suppressor mutations in the prfB gene encoding peptide chain release factor 2 of Escherichia coli.
• Suppression of early competence mutations in Bacillus subtilis by mec mutations.
• Suppression of ctc promoter mutations in Bacillus subtilis.