Key Laboratory of Molecular Epigenetics of MOE and Institute of Genetics & Cytology, Northeast Normal University, Changchun, China.
PLoS One. 2011;6(8):e23896. doi: 10.1371/journal.pone.0023896. Epub 2011 Aug 23.
The Arabidopsis genome contains 18 genes that are predicted to encode Ovate Family Proteins (AtOFPs), a protein family characterized by a conserved OVATE domain, an approximately 70-amino acid domain that was originally found in tomato OVATE protein. Among AtOFP family members, AtOFP1 has been shown to suppress cell elongation, in part, by suppressing the expression of AtGA20ox1, AtOFP4 has been shown to regulate secondary cell wall formation by interact with KNOTTED1-LIKE HOMEODOMAIN PROTEIN 7 (KNAT7), and AtOFP5 has been shown to regulate the activity of a BEL1-LIKEHOMEODOMAIN 1(BLH1)-KNAT3 complex during early embryo sac development, but little is known about the function of other AtOFPs.
METHODOLOGY/PRINCIPAL FINDINGS: We demonstrated here that AtOFP proteins could function as effective transcriptional repressors in the Arabidopsis protoplast transient expression system. The analysis of loss-of-function alleles of AtOFPs suggested AtOFP genes may have overlapping function in regulating plant growth and development, because none of the single mutants identified, including T-DNA insertion mutants in AtOFP1, AtOFP4, AtOFP8, AtOFP10, AtOFP15 and AtOFP16, displayed any apparent morphological defects. Further, Atofp1 Atofp4 and Atofp15 Atofp16 double mutants still did not differ significantly from wild-type. On the other hand, plants overexpressing AtOFP genes displayed a number of abnormal phenotypes, which could be categorized into three distinct classes, suggesting that AtOFP genes may also have diverse functions in regulating plant growth and development. Further analysis suggested that AtOFP1 regulates cotyledon development in a postembryonic manner, and global transcript profiling revealed that it suppress the expression of many other genes.
CONCLUSIONS/SIGNIFICANCE: Our results showed that AtOFPs function as transcriptional repressors and they regulate multiple aspects of plant growth and development. These results provided the first overview of a previously unknown transcriptional repressor family, and revealed their possible roles in plant growth and development.
拟南芥基因组包含 18 个编码卵形家族蛋白（AtOFPs）的基因，该蛋白家族的特征是具有保守的卵形结构域，大约 70 个氨基酸的结构域最初在番茄卵形蛋白中发现。在 AtOFP 家族成员中，AtOFP1 被证明通过抑制 AtGA20ox1 的表达部分抑制细胞伸长，AtOFP4 被证明通过与 KNOTTED1-LIKE HOMEODOMAIN PROTEIN 7（KNAT7）相互作用调节次生细胞壁形成，AtOFP5 被证明在早期胚囊发育过程中调节 BEL1-LIKEHOMEODOMAIN 1（BLH1）-KNAT3 复合物的活性，但对其他 AtOFPs 的功能知之甚少。
方法/主要发现：我们在此证明 AtOFP 蛋白可在拟南芥原生质体瞬时表达系统中作为有效的转录抑制剂发挥作用。AtOFPs 基因的功能丧失等位基因分析表明，AtOFP 基因在调节植物生长发育方面可能具有重叠功能，因为在所鉴定的单个突变体中，包括 AtOFP1、AtOFP4、AtOFP8、AtOFP10、AtOFP15 和 AtOFP16 的 T-DNA 插入突变体，均未显示任何明显的形态缺陷。此外，Atofp1 Atofp4 和 Atofp15 Atofp16 双突变体与野生型仍无显著差异。另一方面，过表达 AtOFP 基因的植物表现出多种异常表型，可分为三类，这表明 AtOFP 基因在调节植物生长发育方面也具有多种功能。进一步分析表明，AtOFP1 以胚胎后方式调节子叶发育，并通过全局转录谱分析表明它抑制许多其他基因的表达。
结论/意义：我们的结果表明，AtOFPs 作为转录抑制剂发挥作用，它们调节植物生长和发育的多个方面。这些结果提供了对一个以前未知的转录抑制剂家族的概述，并揭示了它们在植物生长和发育中的可能作用。
