The Roles of CCCH Zinc-Finger Proteins in Plant Abiotic Stress Tolerance

Abstract

Zinc-finger proteins, a superfamily of proteins with a typical structural domain that coordinates a zinc ion and binds nucleic acids, participate in the regulation of growth, development, and stress adaptation in plants. Most zinc fingers are C2H2-type or CCCC-type, named after the configuration of cysteine (C) and histidine (H); the less-common CCCH zinc-finger proteins are important in the regulation of plant stress responses. In this review, we introduce the domain structures, classification, and subcellular localization of CCCH zinc-finger proteins in plants and discuss their functions in transcriptional and post-transcriptional regulation via interactions with DNA, RNA, and other proteins. We describe the functions of CCCH zinc-finger proteins in plant development and tolerance to abiotic stresses such as salt, drought, flooding, cold temperatures and oxidative stress. Finally, we summarize the signal transduction pathways and regulatory networks of CCCH zinc-finger proteins in their responses to abiotic stress. CCCH zinc-finger proteins regulate the adaptation of plants to abiotic stress in various ways, but the specific molecular mechanisms need to be further explored, along with other mechanisms such as cytoplasm-to-nucleus shuttling and post-transcriptional regulation. Unraveling the molecular mechanisms by which CCCH zinc-finger proteins improve stress tolerance will facilitate the breeding and genetic engineering of crops with improved traits.

Keywords: CCCH zinc-finger proteins; abiotic stresses; plants; regulation pathways; transcription factor.

Figure 1

Putative regulatory mechanism by which CCCH zinc-finger proteins mediate abiotic stress tolerance in plants. (a) Transcription regulation of CCCH zinc-finger protein in the nucleus under abiotic stress. (b) Post-transcriptional regulation of CCCH zinc-finger protein in processing bodies (PBs) and stress granules (SGs) of the cytoplasm under abiotic stress. (c) Protein interaction of CCCH zinc-finger protein in the cytoplasm under abiotic stress. (d) Shuttling of CCCH zinc-finger protein between the nucleus and cytoplasm under abiotic stress. Solid arrows indicate processes that have been verified, and dotted arrows indicate processes that need to be clarified.