Szopa J
Institute of Biochemistry, Wrocław University, Poland.
Acta Biochim Pol. 1995;42(2):183-9.
The nuclear matrices of plant cell nuclei display intrinsic nuclease activity which consists in nicking supercoiled DNA. A cDNA encoding a 32 kDa endonuclease has been cloned and sequenced. The nucleotide and deduced amino-acid sequences show high homology to known 14-3-3 protein sequences from other sources. The amino-acid sequence shows agreement with consensus sequences for potential phosphorylation by protein kinase A and C and for calcium, lipid and membrane-binding sites. The nucleotide-binding site is also present within the conserved part of the sequence. By Northern blot analysis, the differential expression of the corresponding mRNA was detected; it was the strongest in sink tissues. The endonuclease activity found on DNA-polyacrylamide gel electrophoresis coincided with mRNA content and was the highest in tuber.
植物细胞核的核基质表现出内在的核酸酶活性，其作用是切割超螺旋DNA。一个编码32 kDa内切核酸酶的cDNA已被克隆并测序。核苷酸和推导的氨基酸序列与来自其他来源的已知14-3-3蛋白序列具有高度同源性。氨基酸序列与蛋白激酶A和C潜在磷酸化以及钙、脂质和膜结合位点的共有序列一致。核苷酸结合位点也存在于序列的保守部分内。通过Northern印迹分析，检测到相应mRNA的差异表达；在库组织中表达最强。在DNA-聚丙烯酰胺凝胶电泳上发现的内切核酸酶活性与mRNA含量一致，在块茎中最高。
