Weig, A R; Franz, J; Sauer, N; Komor, E: Isolation of a family of cDNA clones from Ricinus communis L. with close homology to the hexose carriers, Journal of Plant Physiology, 143, 178 -183 (1994)
The sugar transport of the so-called group m transport proteins, among them the two so far identified hexose carries from plants, have some strongly conserved sequences in common. Oligonucleotides coding for two conserved regions were constructed to amplify, by polymerase-chain-reaction (PCR), those mRNA species from Ricinus cotyledons that probably code for carrier proteins. Eight different sequences for putative hexose carrier proteins were identified; two of them were completed to full-length clones. Transformation into Saccharomyces cerevisiae showed that one of them definitely codes for an active glucose transport system. The other clone was, though transcribed, not expressed in yeast. The expression frequency was determined by Northern analysis and quantitative PCR. All 8 putative hexose carrier clones were present in only very small amounts in poly(A)-RNA of Ricinus tissues. The identified glucose carrier sequence (Hex3) was predominantely expressed in roots and sink leaves, whereas the other functionally so far unidentified full-length clone (Hex1) was mostly expressed in roots, hypocotyl and source leaf. Both full-length clones showed little or hardly any expression in cotyledons.

Letzte Änderung 13.04.2004