Heitz T, Segond S, Kauffmann S, Geoffroy P, Prasad V, Brunner F, Fritig B, Legrand M
Institut de Biologie Moléculaire des Plantes du C.N.R.S., Université Louis Pasteur, Strasbourg, France.
Mol Gen Genet. 1994 Oct 28;245(2):246-54. doi: 10.1007/BF00283273.
A new PR (pathogenesis-related) protein was isolated from tobacco leaves (Nicotiana tabacum cv. Samsun NN), reacting hypersensitively to tobacco mosaic virus (TMV), by zinc chelate chromatography and was therefore named Pz. Its reactivity toward several lectins indicated the presence of bound sugar residues. From the amino acid sequence of tryptic peptides, Oligonucleotide primers were derived which allowed the synthesis of Pz cDNA by PCR. Using this cDNA as probe, near full-length clones were isolated from a library made from poly(A)+ RNA purified from TMV-infected leaves. Sequence analysis revealed similarities with chitinases/lysozymes of various origins and the purified protein was, indeed, shown to hydrolyse different N-acetylglucosamine-containing substrates. Comparison of peptide and cDNA sequences indicated that Pz protein is synthesized as a pre-pro-protein, a seven-amino acid C-terminal peptide probably being involved in the vacuolar targeting of the protein. Pz mRNA and protein were demonstrated to accumulate strongly in TMV-infected tobacco leaves. Pz transcripts were also found in various tissues of healthy plants, indicating that Pz gene expression is developmentally regulated.
通过锌螯合层析从对烟草花叶病毒（TMV）产生过敏反应的烟草叶片（烟草品种Samsun NN）中分离出一种新的病程相关（PR）蛋白，因此将其命名为Pz。它对几种凝集素的反应表明存在结合的糖残基。根据胰蛋白酶肽段的氨基酸序列设计了寡核苷酸引物，通过PCR合成了Pz cDNA。以该cDNA为探针，从由TMV感染叶片中纯化的poly(A)+ RNA构建的文库中分离出近全长克隆。序列分析显示其与多种来源的几丁质酶/溶菌酶有相似性，并且纯化的蛋白确实能水解不同的含N-乙酰葡糖胺的底物。肽段和cDNA序列的比较表明，Pz蛋白以前体-原蛋白的形式合成，一个七氨基酸的C末端肽可能参与了该蛋白的液泡靶向运输。已证明Pz mRNA和蛋白在TMV感染的烟草叶片中大量积累。在健康植物的各种组织中也发现了Pz转录本，表明Pz基因的表达受发育调控。
