Calmodulin (CaM) is one of the major Ca²⁺-binding proteins in the cells, and it plays multiple roles in several Ca²⁺ signaling pathways and regulating the activities of other proteins. In the present study, we characterized CaM genes from the marine dinoflagellates Amphidinium carterae, Cochlodinium polykrikoides, Prorocentrum micans, and P. minimum, and examined their expression patterns upon the addition and chelation of calcium. Their cDNAs had same ORF length (450 bp) and encoded the same protein, but with few nucleotide differences in the ORF and different 3′- and 5′ untranslated regions (UTRs). The four CaM proteins consist of four EF-hand Ca²⁺-binding motifs, two N-terminal domains and two C-terminal domains, and they were highly conserved within eukaryotes. The CaM gene expressions in the tested species increased by calcium treatments; however, they were significantly down-regulated by the calcium-chelator EGTA. The CaM genes of the test species were inducible and regulated by different calcium doses, suggesting their major role in calcium regulation in dinoflagellates.

钙调蛋白（CaM）是细胞中主要的Ca ²⁺结合蛋白之一，在多种Ca ²⁺信号传导途径和调节其他蛋白的活性中起多种作用。在当前的研究中，我们表征了来自海洋鞭毛藻，角膜两栖动物，多螺旋藻，原球藻和最小拟南芥中的CaM基因，并在添加和螯合钙后检查了它们的表达模式。他们的cDNA具有相同的ORF长度（450 bp），并编码相同的蛋白质，但在ORF和不同的3'-和5'非翻译区（UTR）中核苷酸差异很小。四种CaM蛋白由四个EF手Ca组成²⁺结合基序，两个N末端结构域和两个C末端结构域，它们在真核生物中高度保守。通过钙处理，被测物种中的CaM基因表达增加。但是，钙螯合剂EGTA显着下调了它们。测试物种的CaM基因是可诱导的，并受不同钙剂量的调节，表明它们在藻鞭毛藻中钙调节中的主要作用。