Fig. 1: Atmospheric oxygen sensing regulates tetrapyrrole synthesis via FLU.
From: An oxygen-sensing mechanism for angiosperm adaptation to altitude
a, Schematic representation of the PCO branch of the PRT6 N-degron pathway28. MetAP, methionine amino-peptidase; ATE, arginyl transferase; oxCys, oxidized cysteine. The position of oxygen and possible positions of nitric oxide (NO) in the pathway are shown. Oxygen is used by PCOs to oxidize amino-terminal Cys of ERFVIIs. b, Steady-state Pchlide, measured by fluorescence at 636 nm, in etiolated seedlings of different species grown at different ambient O2 concentrations. c, d, Steady-state Pchlide in Col-0 and erfVII at different ambient O2 concentrations (c) with expression of individual stabilized Cys2Ala mutant ERFVIIs controlled by their native promoters (d)18 (p). e, Amount of FLU RNA transcript in Col-0 and erfVII grown at different ambient O2 concentrations. f, Regulation of FLU orthologue mRNA in P. somniferum (PSOM) and S. lycopersicum (Solyc) grown at various ambient O2 concentrations. g, Schematic of the A. thaliana FLU gene, showing potential ERFVII binding sites (left) and chromatin immunoprecipitation (ChIP) analysis of RAP2.3–HA and HRE2–HA occupancy of FLU gene regions (range indicated by colons); including known positive and negative regulatory sequences20,29 using anti-HA antibody. All experiments were carried out using etiolated seedlings after 5 days growth at pO2 21.2 kPa (48 m a.s.l.) unless otherwise stated. Data are mean ± s.d.; one-way ANOVA. Significantly different groups are indicated by letters in d. n = 3 biologically independent experiments. AU, arbitrary units; R2, coefficient of determination.
