Basset M, Conejero G, Lepetit M, Fourcroy P, Sentenac H
Laboratoire de Biochimie et Physiologie Végétales, ENSA-M, INRA, CNRS URA 573, Montpellier, France.
Plant Mol Biol. 1995 Dec;29(5):947-58. doi: 10.1007/BF00014968.
We have isolated and sequenced the genomic clone coding for the potassium transport system AKT1 of Arabidopsis thaliana. Southern blot analysis indicated that the gene is present in one copy in the Arabidopsis genome. The coding sequence is interrupted by ten introns. Sequence comparisons of AKT1 polypeptide with the voltage-gated inward rectifying Arabidopsis K+ channel KAT1, and with voltage- or cyclic nucleotide-gated channels from insects and mammals, revealed a highly conserved domain found specifically in both plant polypeptides, and corresponding to about the last 50 amino acids of their C-terminal region. Northern blot 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 transcript level.
我们已经分离并测序了拟南芥钾转运系统AKT1的基因组克隆。Southern杂交分析表明该基因在拟南芥基因组中以单拷贝形式存在。编码序列被10个内含子打断。将AKT1多肽与电压门控内向整流拟南芥钾通道KAT1以及昆虫和哺乳动物的电压门控或环核苷酸门控通道进行序列比较，发现了一个高度保守的结构域，该结构域仅在两种植物多肽中特异性存在，并且对应于它们C端区域的最后约50个氨基酸。对拟南芥幼苗中AKT1表达的Northern杂交分析表明，AKT1在根中优先表达。在异养悬浮培养细胞提取物中未检测到转录本。在拟南芥幼苗培养基中耗尽钾4天导致钾组织含量大幅下降（约50%），但不影响AKT1转录本水平。
