Lars-Göran Josefsson

Deletion analysis of a 2S seed storage protein promoter of Brassica napus in transgenic tobacco

The promoter and upstream region of the Brassica napus 2S storage protein napA gene were studied to identify cis-acting sequences involved in developmental seed-specific expression. Fragments generated by successive deletions of the 5′ control region of the napA gene were fused to the reporter gene β-glucuronidase (GUS). These constructs were used to transform tobacco leaf discs. Analyses of GUS activities in mature seeds from the transformed plants indicated that there were both negatively and positively acting sequences in the napin gene promoter. Deletion of sequences between −1101 and −309 resulted in increased GUS activity. In contrast, deletion of sequences between −309 and −211 decreased the expression. The minimum sequence required for seed-specific expression was a 196 bp fragment between −152 and +44. Further 5′ deletion of the fragment to −126 abolished this activity. Sequence comparison showed that a G box-like sequence and two sequence motifs conserved between 2S storage protein genes are located between −148 to −120. Histochemical and fluorometric analysis of tobacco seeds showed that the spatial and developmental expression pattern was retained in the deletion fragments down to −152. However, the expression in tobacco seeds differed from the spatial and temporal expression in B. napus. In tobacco, the napA promoter directed GUS activity early in the endosperm before any visible activity could be seen in the heart-shaped embryo. Later, during the transition from heart to torpedo stages, the main expression of GUS was localized to the embryo. No significant GUS activity was found in either root or leaf.

Evidence for kinship between diverse G-protein coupled receptors

In an earlier publication we described similarities at the primary sequence level between the first probable plant G-protein coupled receptor (GPCR) and three GPCR families (families A, B and F according to Kolakowskis classification) that were previously considered evolutionarily unrelated. Here we analyze further the relatedness among different GPCR families. By using PSI-BLAST, which is a search algorithm that is more potent in detecting weak similarities, one finds additional similarities between GPCR families that have not previously been described. Based on these comparisons, it is possible to divide all the GPCR families into one large clade and two smaller ones. The large clade includes the rhodopsin family (family A), the glucagon receptor family (family B), cyclic AMP receptors (family F), an Arabidopsis thaliana receptor, the Frizzled family and probably also the STE3 pheromone receptors (family E) and vomeronasal receptors type 1. The smaller clades consist of, in one case, BOSS and the GABA-B family of receptors (family C), and in the other the STE2 pheromone receptors (family D) alone. Although our findings are likely to reflect a common ancestry within each of these clades, whether or not two or all three of the clades also share an even more ancient ancestor between them remains an open question that cannot be answered from our present data.

Characterization of a Brassica napus gene encoding a cruciferin subunit: estimation of sizes of cruciferin gene families

A gene encoding a subunit of the 12S storage globulin, cruciferin, in Brassica napus (oilseed rape) has been isolated and characterized. The gene consists of about 2200 bp including three short intervening sequences. Primer extension analysis showed that the major transcription start site is located 30 bp 5′ of the predicted ATG start codon. This gene belongs to one of three different major families encoding cruciferin subunits. By use of gene-family-specific probes and Southern blotting analysis the number of genes of the three different cruciferin subtypes in B. napus was estimated.

An Antigen in Plant Vascular Tissue Cross-Reacts with Antibodies TowardsKLH, Keyhole Limpet Hemocyanin

An Antigen in Plant Vascular Tissue Cross-Reacts with Antibodies Towards KLH, Keyhole Limpet Hemocyanin

Immunolocalisation of a G Protein–Coupled Receptor in Plant TissueSections by Use of a Peptide Antiserum

Immunolocalisation of a G Protein–Coupled Receptor in Plant Tissue Sections by Use of a Peptide Antiserum