Department of Agronomy and Horticulture, Center for Plant Science Innovation , Beadle Center for Biotechnology, University of Nebraska, Lincoln, Nebraska 68588, USA.
Plant Physiol. 2013 Jul;162(3):1359-69. doi: 10.1104/pp.113.218941. Epub 2013 May 15.
Zeins, the maize (Zea mays) prolamin storage proteins, accumulate at very high levels in developing endosperm in endoplasmic reticulum membrane-bound protein bodies. Products of the multigene α-zein families and the single-gene γ-zein family are arranged in the central hydrophobic core and the cross-linked protein body periphery, respectively, but little is known of the specific roles of family members in protein body formation. Here, we used RNA interference suppression of different zein subclasses to abolish vitreous endosperm formation through a variety of effects on protein body density, size, and morphology. We showed that the 27-kilodalton (kD) γ-zein controls protein body initiation but is not involved in protein body filling. Conversely, other γ-zein family members function more in protein body expansion and not in protein body initiation. Reduction in both 19- and 22-kD α-zein subfamilies severely restricted protein body expansion but did not induce morphological abnormalities, which result from reduction of only the 22-kD α-zein class. Concomitant reduction of all zein classes resulted in severe reduction in protein body number but normal protein body size and morphology.
玉米醇溶蛋白，玉米（Zea mays）的醇溶蛋白贮藏蛋白，在质体膜结合的蛋白体中以内质网为积累场所，在发育中的胚乳中高度积累。多基因α-醇溶蛋白家族和单基因γ-醇溶蛋白家族的产物分别排列在中央疏水区和交联蛋白体的外周，但对于家族成员在蛋白体形成中的具体作用知之甚少。在这里，我们通过对蛋白体密度、大小和形态的多种影响，利用不同醇溶蛋白亚类的 RNA 干扰抑制，消除了玻璃态胚乳的形成。我们表明，27kDa 的γ-醇溶蛋白控制蛋白体的起始，但不参与蛋白体的填充。相反，其他γ-醇溶蛋白家族成员在蛋白体的扩张中起作用，而不在蛋白体的起始中起作用。19kDa 和 22kDa 的α-醇溶蛋白亚家族的减少严重限制了蛋白体的扩张，但不会诱导形态异常，这是由于仅减少了 22kDa 的α-醇溶蛋白类。所有醇溶蛋白类的同时减少导致蛋白体数量严重减少，但蛋白体大小和形态正常。
