Project description:Change in gene expression for a wild-type (Nostoc punctiforme ATCC 29133) and hmpD-deletion strain (UCD 543) of Nostoc punctiforme ATCC 29133 over the time course of hormogonium development This study is further descirbed in Risser, D.D. and Meeks, J.C. 2013. Comparative transcriptomics with a motility deficient mutant leads to identification of a novel polysaccharide secretion system in Nostoc punctiforme. Molecular Microbiology
Project description:Change in gene expression for a wild-type (Nostoc punctiforme ATCC 29133) and hmpD-deletion strain (UCD 543) of Nostoc punctiforme ATCC 29133 over the time course of hormogonium development This study is further descirbed in Risser, D.D. and Meeks, J.C. 2013. Comparative transcriptomics with a motility deficient mutant leads to identification of a novel polysaccharide secretion system in Nostoc punctiforme. Molecular Microbiology Total RNA from 3 biological replicates at each time point from 0 to 24 hours after hormogonium induction was converted to cDNA, dye-labled and hybridized to nimblegen 12x135k array slides
Project description:Heterocysts, cells specialized for nitrogen fixation in certain filamentous cyanobacteria, appear singly in a nonrandom spacing pattern along the chain of vegetative cells. A two-stage, biased initiation and competitive resolution model has been proposed to explain the establishment of this spacing pattern. There is substantial evidence that competitive resolution of a subset of cells initiating differentiation occurs by interactions between a self enhancing activator, HetR, and a diffusible inhibitor PatS-5 (RGSGR). Results presented here show that the absence of a unique membrane protein, PatN, in Nostoc punctiforme strain ATCC 29133 leads to a threefold increase in heterocyst frequency and a fourfold decrease in the vegetative cell interval between heterocysts. A PatN-GFP translational fusion shows a pattern of biased inheritance in daughter vegetative cells of ammonium-grown cultures. Inactivation of another heterocyst patterning gene, patA, is epistatic to inactivation of patN, and transcription of patA increases in a patN- deletion strain, implying that patN may function by modulating levels of patA. The presence of PatN is hypothesized to decrease the competency of a vegetative cell to initiate heterocyst differentiation, and the cellular concentration of PatN is dependent on cell division that results in cells transiently depleted of PatN. We suggest that biased inheritance of cell-fate determinants is a phylogenetic domain- spanning paradigm in the development of biological patterns. Change in gene expression for a wild-type (UCD 153) and patN-deletion strain, (UCD 524) of Nostoc punctiforme ATCC 29133 over the time course of heterocyst developments. Total RNA from 3 biological replicates at each time point from 0 to 120 hours after removal of combined nitrogen (Nitrogen step-down) was converted to cDNA, dye-labled and hybridized to nimblegen 12x135k array slides.
