A novel phloem-specific gene is expressed preferentially in aerial portions of Vicia faba.
We have isolated a gene from bean (Vicia faba L.), called Vein1, that encodes a novel protein. The Vein1 cDNA was isolated as a result of a differential screen for genes that are expressed in leaves but not in the most common cell type, the mesophyll cell. Northern blot analysis revealed that Vein 1 transcripts are differentially expressed in the plant with expression in leaves, stems and sepals but not in petals, mesophyll cells or roots. In situ hybridization studies of stem and leaf sections indicate that the expression of Vein1 is localized to the phloem tissue. Interestingly, Vein1 was differentially expressed in stem tissue with the highest expression in the oldest internodes. The deduced Vein1 protein sequence does not share homology with any known protein sequences. The 17 kDa Vein1 protein is highly hydrophilic and contains a histidine-rich motif, where six out of seven amino acids are histidines. The function of Vein1 is unknown, although the expression patterns suggests that it may play a role in mature phloem tissue in the aerial parts of the plant.
Foley
R C
RC
Department of Molecular, Cell and Developmental Biology, University of California Los Angeles 90095-1606, USA.
Liang
Z M
ZM
Singh
K B
KB
D000595:Amino Acid Sequence; D001483:Base Sequence; D018076:DNA, Complementary / Q000235:genetics; D007887:Fabaceae / Q000033:anatomy & histology / Q000737:chemistry / Q000235:genetics*; D015870:Gene Expression; D017343:Genes, Plant; D017403:In Situ Hybridization; D015336:Molecular Probe Techniques; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000096:biosynthesis / Q000235:genetics*; D018520:Plant Shoots / Q000033:anatomy & histology / Q000737:chemistry*; D018547:Plant Stems / Q000737:chemistry; D010946:Plants, Medicinal; D011487:Protein Conformation; D017422:Sequence Analysis, DNA; D014018:Tissue Distribution
D018076:DNA, Complementary; D010940:Plant Proteins; C098795:Vein1 protein, Vicia faba