Botella J R, Arteca R N
Department of Horticulture, Pennsylvania State University, University Park 16802.
Plant Mol Biol. 1994 Mar;24(5):757-66. doi: 10.1007/BF00029857.
Two different calmodulin (CaM) cDNAs (MBCaM-1 and MBCaM-2) were isolated from a vigna radiata lambda gt11 library by screening with a heterologous Arabidopsis cDNA probe (TCH-1). Both cDNAs are 85% homologous inside the coding region but are highly divergent outside this region. The polypeptides encoded by MBCaM-1 and MBCaM-2 are identical except for two conservative substitutions at positions 7 and 10. Southern analysis revealed that both cDNAs are encoded by different genes. Expression studies revealed different patterns of expression of both genes. MBCaM-1 mRNA exhibited a dramatic transient increase in response to touch, while MBCaM-2 expression showed a steady but small increase as compared to MBCaM-1. When plants were grown in complete darkness MBCaM-1 was undetectable and MBCaM-2 exhibited very low levels of expression. One hour after exposure of etiolated seedlings to light MBCaM-1 showed no change, while MBCaM-2 expression was increased. After a 6 h exposure to light there was an induction of both MBCaM-1 and MBCaM-2; however, the magnitude of this increase was much greater for MBCaM-2. When plants were grown under a 16 h light/8 h dark cycle the mRNA levels for MBCaM-1 were lower during the light period and increased during the beginning of the night cycle, while MBCaM-2 showed no change. Plants treated with indole-3-acetic acid had a peak in MBCaM-1 expression 6 h after treatment initiation with a slight decline 3 h after the peak, while MBCaM-2 showed a steady but small increase over time as compared to MBCaM-1. When plants were subjected to salt stress they showed an increase in MBCaM-1 expression 2 h after treatment initiation reaching a maximum after 4 h with no further increase after 6 h, while MBCaM-2 remained unchanged over the time course.
通过用异源拟南芥cDNA探针（TCH - 1）筛选，从豇豆λgt11文库中分离出两种不同的钙调蛋白（CaM）cDNA（MBCaM - 1和MBCaM - 2）。两种cDNA在编码区内的同源性为85%，但在该区域外差异很大。MBCaM - 1和MBCaM - 2编码的多肽除了在第7和第10位有两个保守替换外完全相同。Southern分析表明，两种cDNA由不同的基因编码。表达研究揭示了两种基因不同的表达模式。MBCaM - 1 mRNA在受到触摸刺激后表现出急剧的瞬时增加，而MBCaM - 2的表达与MBCaM - 1相比呈现稳定但较小的增加。当植物在完全黑暗中生长时，检测不到MBCaM - 1，而MBCaM - 2表现出极低的表达水平。黄化幼苗暴露于光照1小时后，MBCaM - 1没有变化，而MBCaM - 2的表达增加。在光照6小时后，MBCaM - 1和MBCaM - 2都被诱导；然而，MBCaM - 2这种增加的幅度要大得多。当植物在16小时光照/8小时黑暗周期下生长时，MBCaM - 1的mRNA水平在光照期间较低，在夜间周期开始时增加，而MBCaM - 2没有变化。用吲哚 - 3 - 乙酸处理的植物在处理开始后6小时MBCaM - 1表达达到峰值，在峰值后3小时略有下降，而MBCaM - 2与MBCaM - 1相比随着时间的推移呈现稳定但较小的增加。当植物受到盐胁迫时，它们在处理开始后2小时MBCaM - 1表达增加，4小时后达到最大值，6小时后不再增加，而MBCaM - 2在整个过程中保持不变。
