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About the Authors:
Elizabeth B. Mearls
Roles Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Resources, Writing - original draft, Writing - review & editing
Affiliation: Department of Biological Sciences, Mount Holyoke College, South Hadley, MA, USA
Jacquelin Jackter
Roles Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Resources
Affiliation: Department of Biological Sciences, Mount Holyoke College, South Hadley, MA, USA
Jennifer M. Colquhoun
Roles Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Resources
Affiliation: Department of Biological Sciences, Lehigh University, Bethlehem, PA, USA
Veronica Farmer
Roles Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Resources
Affiliation: Department of Biological Sciences, Mount Holyoke College, South Hadley, MA, USA
ORCID http://orcid.org/0000-0003-3857-5793
Allison J. Matthews
Roles Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Resources
Affiliation: Department of Biological Sciences, Mount Holyoke College, South Hadley, MA, USA
Laura S. Murphy
† Deceased.
Roles Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Resources
Affiliation: Department of Biological Sciences, Mount Holyoke College, South Hadley, MA, USA
Colleen Fenton
Roles Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Resources
Affiliation: Department of Biological Sciences, Mount Holyoke College, South Hadley, MA, USA
Amy H. Camp
Roles Conceptualization, Data curation, Formal analysis, Funding acquisition, Investigation, Methodology, Project administration, Resources, Supervision, Writing - original draft, Writing - review & editing
* E-mail: [email protected]
Affiliation: Department of Biological Sciences, Mount Holyoke College, South Hadley, MA, USA
ORCID http://orcid.org/0000-0002-2398-6402Abstract
A cascade of alternative sigma factors directs developmental gene expression during spore formation by the bacterium Bacillus subtilis. As the spore develops, a tightly regulated switch occurs in which the early-acting sigma factor [sigma]F is replaced by the late-acting sigma factor [sigma]G. The gene encoding [sigma]G (sigG) is transcribed by [sigma]F and by [sigma]G itself in an autoregulatory loop; yet [sigma]G activity is not detected until [sigma]F-dependent gene expression is complete. This separation in [sigma]F and [sigma]G activities has been suggested to be due at least in part to a poorly understood intercellular checkpoint pathway that delays sigG expression by [sigma]F. Here we report the results of a careful examination of sigG expression during sporulation. Unexpectedly, our findings argue against the existence of a regulatory mechanism to delay sigG transcription by [sigma]F and instead support a model in which sigG is transcribed by [sigma]F with normal timing, but at levels that are very...