Department of Biology, Stanford University, Stanford, CA, USA.
Plant Biotechnol J. 2012 Oct;10(8):925-35. doi: 10.1111/j.1467-7652.2012.00721.x. Epub 2012 Jul 2.
During maize anther development, somatic locular cells differentiate to support meiosis in the pollen mother cells. Meiosis is an important event during anther growth and is essential for plant fertility as pollen contains the haploid sperm. A subset of maize male sterile mutants exhibit meiotic failure, including ms8 (male sterile 8) in which meiocytes arrest as dyads and the locular somatic cells exhibit multiple defects. Systematic proteomic profiles were analysed in biological triplicates plus technical triplicates comparing ms8 anthers with fertile sibling samples at both the premeiotic and meiotic stages; proteins from 3.5 to 20 kDa were fractionated by 1-D PAGE, cleaved with Lys-C and then sequenced using a LTQ Orbitrap Velos MS paradigm. Three hundred and 59 proteins were identified with two or more assigned peptides in which each of those peptides were counted at least two or more times (0.4% peptide false discovery rate (FDR) and 0.2% protein FDR); 2761 proteins were identified with one or more assigned peptides (0.4% peptide FDR and 7.6% protein FDR). Stage-specific protein expression provides candidate stage markers for early anther development, and proteins specifically expressed in fertile compared to sterile anthers provide important clues about the regulation of meiosis. 49% of the proteins detected by this study are new to an independent whole anther proteome, and many small proteins missed by automated maize genome annotation were validated; these outcomes indicate the value of focusing on low molecular weight proteins. The roles of distinctive expressed proteins and methods for mass spectrometry of low molecular weight proteins are discussed.
在玉米花药发育过程中，体细胞小腔细胞分化以支持花粉母细胞的减数分裂。减数分裂是花药生长过程中的一个重要事件，对于植物的育性至关重要，因为花粉中含有单倍体精子。一些玉米雄性不育突变体表现出减数分裂失败，包括 ms8（雄性不育 8），其减数分裂的细胞偶联体停止发育，小腔体细胞表现出多种缺陷。在预减数分裂和减数分裂阶段，对 ms8 花药与可育同胞样本进行了三次生物学重复和三次技术重复的系统蛋白质组学分析；通过 1-D PAGE 分离 3.5 到 20 kDa 的蛋白质，用 Lys-C 切割，然后使用 LTQ Orbitrap Velos MS 模式进行测序。鉴定出 359 种具有两个或更多分配肽的蛋白质，其中每个肽至少分配两次或更多次（0.4%肽假发现率（FDR）和 0.2%蛋白质 FDR）；鉴定出 2761 种具有一个或多个分配肽的蛋白质（0.4%肽 FDR 和 7.6%蛋白质 FDR）。特定于阶段的蛋白质表达为早期花药发育提供了候选的阶段标记，而在可育与不育花药之间特异性表达的蛋白质为减数分裂的调控提供了重要线索。通过这项研究检测到的蛋白质有 49%是独立的全花药蛋白质组中的新蛋白，许多自动玉米基因组注释错过的小蛋白得到了验证；这些结果表明关注低分子量蛋白质的价值。讨论了独特表达蛋白的作用和低分子量蛋白的质谱方法。
