Hokkaido Agriculture Research Center, National Agriculture and Food Research Organization, Hitsujigaoka 1, Toyohira-ku, Sapporo, 062-8555, Japan.
Graduate School of Agriculture, Hokkaido University, Kita-ku, Sapporo, 060-8589, Japan.
New Phytol. 2013 Apr;198(1):95-102. doi: 10.1111/nph.12118. Epub 2013 Jan 16.
Bacterial cold shock proteins (CSPs) act as RNA chaperones that destabilize mRNA secondary structures at low temperatures. Bacterial CSPs are composed solely of a nucleic acid-binding domain termed the cold shock domain (CSD). Plant CSD proteins contain an auxiliary domain in addition to the CSD but also show RNA chaperone activity. However, their biological functions are poorly understood. We examined Arabidopsis COLD SHOCK DOMAIN PROTEIN 2 (AtCSP2) using overexpressing and mutant lines. A double mutant, with reduced AtCSP2 and no AtCSP4, showed higher freezing tolerance than the wild-type when cold-acclimated. The increase in freezing tolerance was associated with up-regulation of CBF transcription factors and their downstream genes. By contrast, overexpression of AtCSP2 resulted in decreased freezing tolerance when cold-acclimated. In addition, late flowering and shorter siliques were observed in the overexpressing lines. AtCSP2 negatively regulates freezing tolerance and is partially redundant with its closest paralog, AtCSP4.
细菌冷休克蛋白 (CSPs) 作为 RNA 伴侣，在低温下使 mRNA 二级结构不稳定。细菌 CSPs 仅由一个称为冷休克结构域 (CSD) 的核酸结合结构域组成。植物 CSD 蛋白除了 CSD 之外还含有一个辅助结构域，但也表现出 RNA 伴侣活性。然而，它们的生物学功能还知之甚少。我们使用过表达和突变系研究了拟南芥冷休克结构域蛋白 2 (AtCSP2)。在经过低温驯化后，与野生型相比，AtCSP2 和 AtCSP4 表达量降低的双突变体具有更高的抗冻性。抗冻性的提高与 CBF 转录因子及其下游基因的上调有关。相反，在经过低温驯化后，过表达 AtCSP2 会导致抗冻性降低。此外，过表达系中观察到开花较晚和雌蕊荚果变短。AtCSP2 负调控抗冻性，与最接近的同源物 AtCSP4 部分冗余。
