title: Heterocyst patterns without patterning proteins in cyanobacterial filaments.
abstract: We have quantitatively modeled heterocyst differentiation after fixed nitrogen step-down in the filamentous cyanobacterium Anabaena sp. PCC 7120 without lateral inhibition due to the patterning proteins PatS or HetN. We use cell growth and division together with fixed-nitrogen dynamics and allow heterocysts to differentiate upon the local exhaustion of available fixed nitrogen. Slow transport of fixed nitrogen along a shared periplasmic space allows for fast growing cells to differentiate ahead of their neighbors. Cell-to-cell variability in growth rate determines the initial heterocyst pattern. Early release of fixed nitrogen from committed heterocysts allows a significant fraction of vegetative cells to be retained at later times. We recover the experimental heterocyst spacing distributions and cluster size distributions of Khudyakov and Golden [Khudyakov, I.Y., Golden, J.W., 2004. Different functions of HetR, a master regulator of heterocyst differentiation in Anabaena sp PCC 7120, can be separated by mutation. Proc. Natl. Acad. Sci. U. S. A. 101, 16040-16045].
authors.affiliation: Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia, Canada B3H 1Z9.
authors.forename: Jun F
authors.initials: JF
authors.lastname: Allard
authors.forename: Alison L
authors.initials: AL
authors.lastname: Hill
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Rutenberg
mesh_terms: D017033:Anabaena / Q000166:cytology* / Q000254:growth & development*; D001426:Bacterial Proteins / Q000378:metabolism*; D002455:Cell Division; D008954:Models, Biological; D009586:Nitrogen Fixation; D013997:Time Factors
chemical_list: D001426:Bacterial Proteins