Chandra A, Upadhyaya K C
Molecular Genetics Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India.
Cell Mol Biol Res. 1993;39(5):509-16.
The calcium binding protein calmodulin is involved in regulating various cellular and biochemical processes. A gene for calmodulin has been isolated from a genomic library of Arabidopsis thaliana constructed in lambda EMBL-4 using a heterologous cDNA probe from electric eel. The genomic clone was found to contain a complete copy of a distinct calmodulin (CaM) gene. A comparison of the nucleotide sequence with those from the other plant and animal systems reveals that the Arabidopsis CaM gene contains two exons and a single intron of 364 bp. The intron splits the triplet encoding the 25th amino acid of the protein. The Arabidopsis calmodulin protein appears to be distinct in containing a single amino acid substitution, arg to lys at the 126th position from the other known plant and animal calmodulins. The 5'-upstream region of this CaM gene (ACaM4) contains several known sequence-elements, a few of which are known to be implicated in transcriptional activation in response to light, U.V. radiation and heat shock besides the presence of many small multiple repeats. The Southern hybridization analysis and a comparison of nucleotide sequence with those of the other calmodulin genes of Arabidopsis indicate that the calmodulin gene, ACaM4, belongs to a small multigene family consisting of at least four members in the Arabidopsis genome.
钙结合蛋白钙调蛋白参与调节各种细胞和生化过程。利用来自电鳗的异源cDNA探针，从构建于λEMBL - 4载体中的拟南芥基因组文库中分离出一个钙调蛋白基因。发现该基因组克隆包含一个完整的、独特的钙调蛋白（CaM）基因拷贝。将该核苷酸序列与来自其他植物和动物系统的序列进行比较，发现拟南芥CaM基因包含两个外显子和一个364 bp的单一内含子。该内含子将编码该蛋白第25个氨基酸的三联体分开。拟南芥钙调蛋白与其他已知的植物和动物钙调蛋白相比，似乎在第126位含有一个单一的氨基酸取代，即从精氨酸变为赖氨酸。该CaM基因（ACaM4）的5'上游区域包含几个已知的序列元件，除了存在许多小的多重重复序列外，其中一些已知与响应光、紫外线辐射和热休克的转录激活有关。Southern杂交分析以及将该核苷酸序列与拟南芥其他钙调蛋白基因的序列进行比较表明，钙调蛋白基因ACaM4属于一个小的多基因家族，在拟南芥基因组中至少由四个成员组成。
