Mirco Geisler

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Wild-type stomata are spaced by intervening cells, a pattern disrupted in the Arabidopsis mutant too many mouths (tmm). To determine the mechanism of wild-type spacing and how tmm results in pattern violations, we analyzed the behavior of cells through time by using sequential dental resin impressions. Meristemoids are stomatal precursors produced by(More)
Several lines of evidence suggest that regulation of intracellular Ca(2+) levels is crucial for adaptation of plants to environmental stress. We have cloned and characterized Arabidopsis auto-inhibited Ca(2+)-ATPase, isoform 4 (ACA4), a calmodulin-regulated Ca(2+)-ATPase. Confocal laser scanning data of a green fluorescent protein-tagged version of ACA4 as(More)
Recent genomic data in the model plant Arabidopsis thaliana reveal the existence of at least 11 Ca(2+)-ATPase genes, and an analysis of expressed sequence tags suggests that the number of calcium pumps in this organism might be even higher. A phylogenetic analysis shows that 11 Ca(2+)-ATPases clearly form distinct groups, type IIA (or ECA for ER-type(More)
The lipid composition of membranes is a key determinant for cold tolerance, and enzymes that modify membrane structure seem to be important for low-temperature acclimation. We have characterized ALA1 (for aminophospholipid ATPase1), a novel P-type ATPase in Arabidopsis that belongs to the gene family ALA1 to ALA11. The deduced amino acid sequence of ALA1 is(More)
A Ca(2+)-ATPase was purified from plasma membranes (PM) isolated from Arabidopsis cultured cells by calmodulin (CaM)-affinity chromatography. Three tryptic fragments from the protein were microsequenced and the corresponding cDNA was amplified by polymerase chain reaction using primers designed from the microsequences of the tryptic fragments. At-ACA8(More)
Polarized transport of the plant hormone auxin influences multiple growth processes in plants and is regulated by plasma-membrane-localized efflux and uptake carriers. The PGP (P-glycoprotein) ABC transporters (ATP-binding-cassette transporters), PIN (pin-formed) subfamily of major facilitator proteins and members of AUX/LAX families have been shown to(More)
The molybdenum cofactor (Moco) forms part of the catalytic center in all eukaryotic molybdenum enzymes and is synthesized in a highly conserved pathway. Among eukaryotes, very little is known about the processes taking place subsequent to Moco biosynthesis, i.e. Moco transfer, allocation, and insertion into molybdenum enzymes. In the model plant Arabidopsis(More)
The molybdenum cofactor (Moco) is a prosthetic group required by a number of enzymes, such as nitrate reductase, sulfite oxidase, xanthine dehydrogenase, and aldehyde oxidase. Its biosynthesis in eukaryotes can be divided into four steps, of which the last three are proposed to occur in the cytosol. Here, we report that the mitochondrial ABC transporter(More)
Two functional human genes coding for 7 S RNA species K and L were analyzed for promoter requirements by in vitro transcription experiments with cytoplasmic S-100 extracts. Since accurate and efficient transcription of both genes is dependent on the presence of 5'-flanking sequences, hybrid genes representing crossover fusions between the 5' external(More)
The molybdenum cofactor (Moco) is the active compound at the catalytic site of molybdenum enzymes. Moco is synthesized by a conserved four-step pathway involving six proteins in Arabidopsis thaliana. Bimolecular fluorescence complementation was used to study the subcellular localization and interaction of those proteins catalysing Moco biosynthesis. In(More)