Structure and function of the Bacillus SpoIIE protein and its localization to sites of sporulation septum assembly.
Functioning of the spoIIE locus of Bacillus subtilis is required for formation of a normal polar septum during sporulation and for activation of the transcription factor sigma F, which directs early forespore-specific gene expression. We have determined the DNA sequence of the wild type and several mutant alleles of the spoIIE gene of B. subtilis and sequenced a substantial portion of its presumptive homologue in Bacillus megaterium. We show that the spoIIE locus encodes a single large protein with a predicted molecular mass of 92 kDa. Each of five point-mutation alleles, which have traditionally defined the locus, and two transposon-generated mutations were shown to fall within the coding sequence for the 92 kDa gene product or within sequences expected to be required for its expression. The amino-terminal portion of the predicted SpoIIE gene product, comprising approximately 40% of the protein, is extremely hydrophobic and is expected to contain up to 12 membrane-spanning segments. The remainder of the protein contains no hydrophobic segments long enough to span a lipid bilayer and is therefore presumed to comprise one or more globular, aqueous-phase exposed domains. An in-frame fusion joining the 3' end of the B. megaterium spoIIE coding sequence to the 5' end of gfp, a gene encoding the green fluorescent protein (GFP) of Aquorea victoria, resulted in a strong, sporulation-specific fluorescent signal localized to the sites of sporulation septum assembly. We speculate that SpoIIE plays a role in assembling the sporulation septum, perhaps determining the special properties of the structure that permit intercompartment signalling during development.
Barák
I
I
Department of Genetics, University of Georgia, Athens 30602, USA.
Behari
J
J
Olmedo
G
G
Guzmán
P
P
Brown
D P
DP
Castro
E
E
Walker
D
D
Westpheling
J
J
Youngman
P
P
D000483:Alleles; D000595:Amino Acid Sequence; D001410:Bacillus megaterium / Q000502:physiology; D001412:Bacillus subtilis / Q000502:physiology*; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D001483:Base Sequence; D015153:Blotting, Western; D004269:DNA, Bacterial; D005816:Genetic Complementation Test; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000235:genetics; D008969:Molecular Sequence Data; D009154:Mutation; D011993:Recombinant Fusion Proteins / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D012808:Sigma Factor; D013171:Spores, Bacterial; D014157:Transcription Factors
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D008164:Luminescent Proteins; D011993:Recombinant Fusion Proteins; D012808:Sigma Factor; D014157:Transcription Factors; C092468:spoIIR protein, Bacillus subtilis; C030069:spore-specific proteins, Bacillus; D049452:Green Fluorescent Proteins