INCREASED EXPRESSION OF THE MAIZE IMMUNOGLOBULIN BINDING-PROTEIN HOMOLOG B-70 IN 3 ZEIN REGULATORY MUTANTS
INCREASED EXPRESSION OF THE MAIZE IMMUNOGLOBULIN BINDING-PROTEIN HOMOLOG B-70 IN 3 ZEIN REGULATORY MUTANTS
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DOI：
10.1105/tpc.3.5.497
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发表时间：
1991-05-01
期刊：
影响因子：
11.6
通讯作者：
WROBEL, RL
中科院分区：
文献类型：
--
作者：
BOSTON, RS;FONTES, EBP;WROBEL, RL
携带floury-2、有缺陷的胚乳-B30 或Mucronate 突变的植物过量产生b-70，这是哺乳动物免疫球蛋白结合蛋白的玉米同源物。在这些突变体的胚乳发育过程中，b-70 蛋白和 RNA 的水平在授粉后 14 天到 20 天之间急剧增加。在后期阶段，b-70 RNA 水平下降，而蛋白质水平仍然很高。 b-70 RNA 水平的增加是胚乳特异性的，并且依赖于floury-2 突变体中的基因剂量。在所有三种突变体中，b-70 RNA 和蛋白质水平的增加与玉米醇溶蛋白合成的变化成反比。虽然b-70多肽可以从纯化的蛋白体中提取，但它们携带羧基末端内质网保留信号HDEL。我们认为，这些突变体中 b-70 的诱导是对异常折叠或不正确组装的储存蛋白的细胞反应，并且可能反映了其作为多肽链结合蛋白的作用。
Plants carrying floury-2, Defective endosperm-B30, or Mucronate mutations overproduce b-70, a maize homolog of the mammalian immunoglobulin binding protein. During endosperm development in these mutants, levels of both b-70 protein and RNA increase dramatically between 14 days and 20 days after pollination. At later stages, b-70 RNA levels decline while protein levels remain high. The increase in b-70 RNA levels is endosperm specific and dependent on gene dosage in the floury-2 mutant. In all three mutants, the increases in b-70 RNA and protein levels are inversely proportional to changes in zein synthesis. Although b-70 polypeptides can be extracted from purified protein bodies, they carry a carboxy-terminal endoplasmic reticulum retention signal, HDEL. We propose that induction of b-70 in these mutants is a cellular response to abnormally folded or improperly assembled storage proteins and probably reflects its role as a polypeptide chain binding protein.