title: Bacillus subtilis Pro-sigmaE fusion protein localizes to the forespore septum and fails to be processed when synthesized in the forespore.
abstract: Endospore formation in Bacillus subtilis begins with an asymmetric cell division that partitions the bacterium into mother cell and forespore compartments. Mother cell-specific gene expression is initiated by sigmaE, a transcription factor that is active only in the mother cell but which existed as an inactive precursor (pro-sigmaE) in the predivisional cell. Activation of pro-sigmaE involves the removal of 27 amino acids from its amino terminus. A chimera of pro-sigmaE and the green fluorescent protein (GFP) was expressed from either the normal sigE promoter (P(spoIIG)), which places pro-sigmaE::GFP in both mother cell and forespore compartments, or the forespore-specific promoter (P(dacF)), which produces pro-sigmaE::GFP only in the forespore compartment. The pro-sigmaE::GFP expressed from P(spoIIG), but not P(dacF), was converted to a lower-molecular-weight form by a mechanism dependent on gene products (SpoIIGA and sigmaF) that are essential for normal pro-sigmaE processing. This finding is consistent with the pro-sigmaE processing reaction occurring only in the mother cell compartment. In processing-deficient cells, pro-sigmaE::GFP was found to accumulate at the septal membrane, a location where its processing apparatus would be susceptible to triggering from the adjoining forespore.
authors.affiliation: Department of Microbiology, University of Texas Health Science Center at San Antonio, 78284-7758, USA.
authors.forename: J
authors.initials: J
authors.lastname: Ju
authors.forename: T
authors.initials: T
authors.lastname: Luo
authors.forename: W G
authors.initials: WG
authors.lastname: Haldenwang
mesh_terms: D001412:Bacillus subtilis / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D015153:Blotting, Western; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D011498:Protein Precursors / Q000235:genetics / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012808:Sigma Factor / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D008164:Luminescent Proteins; D011498:Protein Precursors; D011993:Recombinant Fusion Proteins; D012808:Sigma Factor; D014157:Transcription Factors; C063202:sporulation-specific sigma factors; D049452:Green Fluorescent Proteins