Mizoguchi T, Yamaguchi-Shinozaki K, Hayashida N, Kamada H, Shinozaki K
Laboratory of Plant Molecular Biology, Tsukuba Life Science Center, RIKEN (The Institute of Physical and Chemical Research), Ibaraki, Japan.
Plant Mol Biol. 1993 Jan;21(2):279-89. doi: 10.1007/BF00019944.
Two cDNA clones, ATCKA1 and ATCKA2, encoding casein kinase II (CKII) catalytic subunits, were cloned from Arabidopsis thaliana and their nucleotide sequences were determined. Both cDNAs contain 999 bp open reading frames and are 94% identical on the amino acid sequence level. The deduced amino acid sequences of ATCKA1 and ATCKA2 are very similar to that of the human CKII catalytic alpha subunit (72% homology). Northern blot analysis indicates that the ATCKA1 and ATCKA2 mRNAs are present in all plant organs, but that ATCKA1 transcript levels are quite low compared to those of ATCKA2. Genomic Southern blot analysis suggests that there are at least three CKII genes in the A. thaliana genome. We expressed the ATCKA1 and ATCKA2 cDNAs in Escherichia coli using a pET vector derivative and analyzed the expressed protein in vitro. The expressed ATCKA1 protein phosphorylated casein using either ATP or GTP. This activity was inhibited by heparin, indicating that the expressed protein has activity similar to those reported for animal and yeast CKII.
从拟南芥中克隆出了两个编码酪蛋白激酶II（CKII）催化亚基的cDNA克隆，即ATCKA1和ATCKA2，并测定了它们的核苷酸序列。这两个cDNA均包含999 bp的开放阅读框，在氨基酸序列水平上具有94%的同一性。ATCKA1和ATCKA2推导的氨基酸序列与人类CKII催化α亚基的序列非常相似（同源性为72%）。Northern印迹分析表明，ATCKA1和ATCKA2的mRNA存在于所有植物器官中，但与ATCKA2相比，ATCKA1的转录水平相当低。基因组Southern印迹分析表明，拟南芥基因组中至少有三个CKII基因。我们使用pET载体衍生物在大肠杆菌中表达了ATCKA1和ATCKA2的cDNA，并在体外分析了表达的蛋白质。表达的ATCKA1蛋白使用ATP或GTP均可使酪蛋白磷酸化。这种活性受到肝素的抑制，表明表达的蛋白具有与报道的动物和酵母CKII相似的活性。
