Cloning and characteristics of a novel gene HbUEP from latex in Hevea brasiliensis

HbUEP, an ubiquitin extension protein gene from latex of the rubber tree (Hevea brasiliensis) was cloned and sequenced using a differentially ethphon-induced expressed cDNA subtraction library. The cDNA had 771 bp nucleotides, comprising a 226 bp 3′ untranslated region (UTR), 77 bp 5′UTR and a 468 bp open reading frame encoding a 156 amino acid peptide. Southern blotting analysis showed that this gene was a low copy number gene in the H. brasiliensis genome. Within 24 h after application of ethphon, the gene was expressed weakly in both control and latex sampled at 6 h, and strongly in latex sampled at 12 h, showing that this gene expression could be regulated by ethphon. Ethphon could increase the latex yield in H. brasiliensis. It is suggested that the HbUEP gene may be involved in the regulation of ethphon-induced high latex yield in H. brasiliensis.

Structure, properties and enhanced expression of galactose-binding C-type lectins in mucous cells of gills from freshwater Japanese eels (Anguilla japonica)

Using a Japanese-eel (Anguilla japonica) gill cDNA subtraction library, two novel β-d-galactose-binding lectins were identified that belong to group VII of the animal C-type lectin family. The eel C-type lectins, termed eCL-1 and eCL-2, are simple lectins composed of 163 amino acid residues, including a 22-residue signal peptide for secretion and a single carbohydrate-recognition domain (CRD) of ∼ 130 residues typical of C-type lectins. The galactose specificity of the CRD was suggested by the presence of a QPD motif and confirmed by a competitive binding assay. Using Ruthenium Red staining, the lectins were shown to bind Ca2+ ions. SDS/PAGE showed that native eCL-1 and eCL-2have an SDS-resistant octameric structure (a tetramer of disulphide-linked dimers). Northern and Western blot analyses demonstrated high-level expression of eCL-1 and eCL-2 mRNAs and their protein products in gills from freshwater eels, which decreased markedly when the eels were transferred from freshwater to seawater. Immunohistochemistry showed that the eel lectins are localized in the exocrine mucous cells of the gill.