M. Basset et al., ORGANIZATION AND EXPRESSION OF THE GENE CODING FOR THE POTASSIUM-TRANSPORT SYSTEM AKT1 OF ARABIDOPSIS-THALIANA, Plant molecular biology, 29(5), 1995, pp. 947-958
We have isolated and sequenced the genomic clone coding for the potass
ium transport system AKT1 of Arabidopsis thaliana. Southern blot analy
sis indicated that the gene is present in one copy in the Arabidopsis
genome. The coding sequence is interrupted by ten introns. Sequence co
mparisons of AKT1 polypeptide with the voltage-gated inward rectifying
Arabidopsis K+ channel KAT1, and with voltage-or cyclic nucleotide-ga
ted channels from insects and mammals, revealed a highly conserved dom
ain found specifically in both plant polypeptides, and correponding to
about the last 50 amino acids of their C-terminal region. Northern bl
ot analysis of AKT1 expression in Arabidopsis seedlings indicated that
AKT1 is preferentially expressed in roots. No transcript was detected
in extracts from heterotrophic suspension culture cells. Depleting K in the Arabidopsis seedling culture medium for 4 days led to a strong
decrease in K+ tissue content (ca. 50%), but did not affect AKT1 tran
script level.