Two Developmental Genes Encoding σ Factor Homologs are Arranged in Tandem in Bacillus subtilis
- Resource Type
- research-article
- Authors
- Masuda, Esteban S.; Anaguchi, Hiroyuki; Yamada, Kazunori; Kobayashi, Yasuo
- Source
- Proceedings of the National Academy of Sciences of the United States of America, 1988 Oct . 85(20), 7637-7641.
- Subject
- Genetics
Spore Formation
Transcriptional Regulation
Deletion Mutation
Genes
Sporulation
Plasmids
DNA
Amino acids
RNA
Genetic mutation
Somatic cells
Gene expression regulation
Open reading frames
- Language
- English
- ISSN
- 00278424
The sporulation-essential gene spoIIG of the Gram-positive bacterium Bacillus subtilis encodes the sporulation-specific σ factor σ 29(σ E). We report here the initial characterization of a gene, referred to as ORF3, located immediately downstream of the spoIIG gene. The results indicate that ORF3 encodes a σ homolog, whose expression is highly regulated during development. Analysis of the ORF3 nucleotide sequence reveals an open reading frame encoding a polypeptide of 260 amino acid residues (molecular mass of 30.1 kDa). Its predicted amino acid sequence shows significant similarity to that of other RNA polymerase σ factor sequences. S1 nuclease mapping experiments indicate that ORF3 is initially cotranscribed with spoIIG from about 1 to 4 hr into the sporulation process and that later on ORF3 is transcribed independently from a new site located between spoIIG and ORF3. The role of ORF3 was investigated by constructing a deletion mutation in its structural gene. The mutant exhibits normal growth but is unable to produce heat-resistant spores. We propose that the ORF3 gene product is a σ factor or a related peptide essential for sporulation at a late stage of development.