Synthesis, processing and export of cytoplasmic endo-ß-1,4-xylanase from barley aleurone during germination

We have identified the major endo-β-l,4-xylanase (XYN-1) in the aleurone of germinating barley grain, and show that it is expressed as a precursor of Mr 61 500 with both N- and C-terminal propeptides. XYN-1 is synthesized as an inactive enzyme in the cytoplasm, and only becomes active at a late stage of germination when the aleurone ceases to...

Effects of modulation of calcium levels and calcium fluxes on ABA- induced gene expression in barley aleurone

We present data to elucidate the involvement of calcium ions in abscisic acid (ABA)-induced gene expression. Modulation of external calcium concentrations was able to affect ABA-induced specific RAB gene expression. At a constant ABA level with increasing extracellular calcium level, an increasing RAB mRNA expression was measured. In barley...

Detection of GTP-binding proteins in barley aleurone protoplasts

We report the existence of several families of GTP-binding proteins in barley aleurone protoplasts. Partial purified plasma membrane proteins were separated by SDS-PAGE, transferred to a nitrocellulose filter and incubated with either antisera raised against a highly conserved animal G protein alpha subunit peptide/or Ras protein, or with [alpha...

Abscisic acid induces a cytosolic calcium decrease in barley aleurone protoplasts

Cytosolic calcium concentrations (Ca(i)) of barley aleurone protoplasts after stimulation with the plant hormone abscisic acid (ABA) were measured by using the calcium-sensitive fluorescent dye Indo-1. The measuredd basal Ca(i) is about 200 nM. Stimulation with ABA induces a strong dose-dependent decrease in Ca(i) to a minimal value of about 50...