The prespore-specific activation of sigma factor SigF (sigma(F)) in Bacillus subtilis has been explained mainly by two factors, i.e., the transient genetic asymmetry and the volume difference between the mother cell and the prespore. Here, we systematically surveyed the effect of these two factors on sporulation using a quantitative modeling and simulation architecture named hybrid functional Petri net with extension (HFPNe). Considering the fact that the transient genetic asymmetry and the volume difference in sporulation of B. subtilis finally bring about the concentration difference in two proteins SpoIIAB (AB) and SpoIIAA (AA) between the mother cell and the prespore, we have surveyed the effect of AB and AA concentration on the prespore-specific activation of sigma(F) occurring in the early stage of sporulation. Our results show that the prespore-specific activation of sigma(F) could be governed by the ratio of AA to AB rather than their concentrations themselves. Our model also suggests that B. subtilis could maximize the ratio of AA to AB in the prespore and minimize it in the mother cell by employing both the transient genetic asymmetry and the volume difference simultaneously. This might give a good explanation to the co-occurrence of the transient asymmetry and the volume difference during sporulation of B. subtilis. In addition, we suggest for the first time that the sigma(F) activation in the prespore might be switched off by the decrease in the ratio of AA to AB after the transient genetic asymmetry is to an end by completion of DNA translocation into the prespore.
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http://dx.doi.org/10.1016/j.biosystems.2010.03.002 | DOI Listing |
Biomolecules
November 2013
Division of Molecular Neurobiology, Institute for Enzyme Research, The University of Tokushima, Kuramoto-cho, Tokushima 770-8503, Japan.
In eukaryotic cells, mitochondria are self-reproducing organelles with their own DNA and they play a central role in adenosine triphosphate (ATP) synthesis by respiration. Increasing evidence indicates that mitochondria also have critical and multiple functions in the initiation of cell differentiation, cell-type determination, cell movement, and pattern formation. This has been most strikingly realized in development of the cellular slime mold Dictyostelium.
View Article and Find Full Text PDFPLoS One
May 2012
College of Life Sciences, University of Dundee, Dundee, United Kingdom.
In response to the signaling polyketide DIF-1 DimB directly activates transcription of the ecmB gene in pstB cells; a subset of the prestalk cells that are the precursors of the basal disc. We show that the promoter of pspA, a prespore-specific gene, also contains a DimB binding site. Mutation of this site causes ectopic expression in the prestalk region and ChIP analysis shows that DIF-1 induces binding of DimB to the pspA promoter.
View Article and Find Full Text PDFDev Growth Differ
May 2010
Biological Laboratory, Kansai Medical University, Hirakata, Osaka, Japan.
Prespore cell-inducing (psi, psi) factor (PsiA), encoded by the psiA gene of Dictyostelium, is a secreted signal glycoprotein that induces prespore cell differentiation when added to monolayer cultures. In situ hybridization during normal development showed that the psiA gene is highly expressed in scattered cells at the mound stage and in prespore cells at the onset of culmination. The conventional prespore-cell marker genes, cotC and pspA, were expressed normally in psiA(-) and psiA overexpressing strains.
View Article and Find Full Text PDFBiosystems
June 2010
Human Genome Center, Institute of Medical Science, University of Tokyo, Minato-ku, Tokyo, Japan.
The prespore-specific activation of sigma factor SigF (sigma(F)) in Bacillus subtilis has been explained mainly by two factors, i.e., the transient genetic asymmetry and the volume difference between the mother cell and the prespore.
View Article and Find Full Text PDFJ Bacteriol
December 2008
Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Avenida da República, Apartado 127, 2781-901 Oeiras Codex, Portugal.
Activation of the late prespore-specific RNA polymerase sigma factor sigma(G) during Bacillus subtilis sporulation coincides with completion of the engulfment process, when the prespore becomes a protoplast fully surrounded by the mother cell cytoplasm and separated from it by a double membrane system. Activation of sigma(G) also requires expression of spoIIIJ, coding for a membrane protein translocase of the YidC/Oxa1p/Alb3 family, and of the mother cell-specific spoIIIA operon. Here we present genetic and biochemical evidence indicating that SpoIIIAE, the product of one of the spoIIIA cistrons, and SpoIIIJ interact in the membrane, thereby linking the function of the spoIIIJ and spoIIIA loci in the activation of sigma(G).
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