The "pro" sequence of the sporulation-specific sigma transcription factor sigma(E) directs it to the mother cell side of the sporulation septum.
sigma(E), a mother cell-specific transcription factor of sporulating Bacillus subtilis, is derived from an inactive precursor protein (pro-sigma(E)). Activation of sigma(E) occurs when a sporulation-specific protease (SpoIIGA) cleaves 27 amino acids from the pro-sigma(E) amino terminus. This reaction is believed to take place at the mother cell-forespore septum. Using a chimera of pro-sigma(E) and green fluorescent protein (GFP) to visualize the intracellular location of pro-sigma(E) by fluorescence microscopy, and lysozyme treatment to separate the mother cell and forespore compartments, we determined that the pro-sigma(E)::GFP signal, localized to the forespore septum prior to lysozyme treatment, is restricted to the mother cell compartment after treatment. Thus, pro-sigma(E)::GFP had been sequestered to the mother cell side of the septum. This segregation of pro-sigma(E)::GFP, and presumably pro-sigma(E), to the mother cell is likely to be the reason why sigma(E) activity is restricted to that compartment.
Ju
J
J
Department of Microbiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78284-7758, USA.
Haldenwang
W G
WG
D001412:Bacillus subtilis / Q000502:physiology*; D001426:Bacterial Proteins / Q000378:metabolism; D001692:Biological Transport; D002451:Cell Compartmentation; D010450:Endopeptidases / Q000378:metabolism; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D010447:Peptide Hydrolases; D011498:Protein Precursors / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D021382:Protein Sorting Signals / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012808:Sigma Factor / Q000235:genetics / Q000378:metabolism*; D013171:Spores, Bacterial; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
D001426:Bacterial Proteins; D008164:Luminescent Proteins; D008565:Membrane Proteins; D011498:Protein Precursors; D021382:Protein Sorting Signals; D011993:Recombinant Fusion Proteins; D012808:Sigma Factor; D014157:Transcription Factors; C112175:pro-sigmaE protein, Bacillus subtilis; D049452:Green Fluorescent Proteins; D010450:Endopeptidases; D010447:Peptide Hydrolases; C071976:SpoIIGA protein, Bacillus subtilis