Mun J H, Yu H J, Lee H S, Kwon Y M, Lee J S, Lee I, Kim S G
School of Biological Sciences Seoul National University, Seoul 151-742, South Korea.
Gene. 2000 Oct 31;257(2):167-76. doi: 10.1016/s0378-1119(00)00412-1.
Actin-depolymerizing factor (ADF) is one of the small actin-binding proteins that regulate actin dynamics in cells. We have isolated two cDNA clones, PhADF1 and PhADF2, encoding ADF from cDNA libraries constructed from petal protoplast cultures and flowers of Petunia hybrida. PhADF1 and PhADF2 encode polypeptides of 139 and 143 amino acids with a calculated molecular mass of 16.04 and 16.51kDa, respectively. Co-sedimentation assay showed that the recombinant PhADF1 protein produced in Escherichia coli binds to F-actin at pH7. 0 and preferentially depolymerizes it at pH8.0. Gene tree analysis indicates that the plant ADF family can be grouped into four classes, and PhADFs are included in class I. Southern blot analyses revealed that one or two copies of PhADF genes are present in petunia genome, and several other related isoforms also exist. Northern blot analyses indicated that PhADF1 and PhADF2 are closely related and abundantly expressed in every plant organ except pollen. In addition, they are highly accumulated in mature vegetative tissue (petal, leaf, and stem). Our results indicate that the transcription of petunia ADF genes is differentially regulated by developmental signals.
肌动蛋白解聚因子（ADF）是调节细胞中肌动蛋白动力学的小肌动蛋白结合蛋白之一。我们从矮牵牛花瓣原生质体培养物和花朵构建的cDNA文库中分离出两个编码ADF的cDNA克隆，即PhADF1和PhADF2。PhADF1和PhADF2分别编码139和143个氨基酸的多肽，计算分子量分别为16.04和16.51kDa。共沉降分析表明，在大肠杆菌中产生的重组PhADF1蛋白在pH7.0时与F-肌动蛋白结合，并在pH8.0时优先使其解聚。基因树分析表明，植物ADF家族可分为四类，PhADF属于第一类。Southern印迹分析显示，矮牵牛基因组中存在一或两个PhADF基因拷贝，还存在其他几个相关的异构体。Northern印迹分析表明，PhADF1和PhADF2密切相关，且在除花粉外的每个植物器官中均大量表达。此外，它们在成熟营养组织（花瓣、叶片和茎）中高度积累。我们的结果表明，矮牵牛ADF基因的转录受发育信号的差异调节。
