AtC3H17, a Non-Tandem CCCH Zinc Finger Protein, Functions as a Nuclear Transcriptional Activator and Has Pleiotropic Effects on Vegetative Development, Flowering and Seed Development in Arabidopsis

Abstract

Despite increasing reports that CCCH zinc finger proteins function in plant development and stress responses, the functions and molecular aspects of many CCCH zinc finger proteins remain uncharacterized. Here, we characterized the biological and molecular functions of AtC3H17, a unique Arabidopsis gene encoding a non-tandem CCCH zinc finger protein. AtC3H17 was ubiquitously expressed throughout the life cycle of Arabidopsis plants and their organs. The rate and ratio of seed germination of atc3h17 mutants were slightly slower and lower, respectively, than those of the wild type (WT), whereas AtC3H17-overexpressing transgenic plants (OXs) showed an enhanced germination rate. atc3h17 mutant seedlings were smaller and lighter than WT seedlings while AtC3H17 OX seedlings were larger and heavier. In regulation of flowering time, atc3h17 mutants showed delayed flowering, whereas AtC3H17 OXs showed early flowering compared with the WT. In addition, overexpression of AtC3H17 affected seed development, displaying abnormalities compared with the WT. AtC3H17 protein was localized to the nucleus and showed transcriptional activation activity in yeast and Arabidopsis protoplasts. The N-terminal region of AtC3H17, containing a conserved EELR-like motif, was necessary for transcriptional activation activity, and the two conserved glutamate residues in the EELR-like motif played an important role in transcriptional activation activity. Real-time PCR and transactivation analyses showed that AtC3H17 might be involved in seed development via transcriptional activation of OLEO1, OLEO2 and CRU3. Our results suggest that AtC3H17 has pleiotropic effects on vegetative development such as seed germination and seedling growth, flowering and seed development, and functions as a nuclear transcriptional activator in Arabidopsis.

Identification of QTLs for Domestication-Related Traits in Zombi Pea [Vigna vexillata (L.) A. Rich], a Lost Crop of Africa

“…Plant zinc finger proteins comprise a large protein family and have diverse functions related to plant development and resistance to biotic and abiotic stresses. The Arabidopsis genes AtC3H17, AtZFP1, AtKHZ1, and AtKHZ2 as well as the Medicago sativa gene MsZFN, encoding CCCH zinc finger proteins, influence flowering time (Chao et al, 2014;Seok et al, 2016;Yan et al, 2017;.…”

BcMF30a and BcMF30c, Two Novel Non-Tandem CCCH Zinc-Finger Proteins, Function in Pollen Development and Pollen Germination in Brassica campestris ssp. chinensis

“…Fetal liver zinc finger protein 1 (Fliz1), a zebrafish CCCH zinc-finger protein, acts as a transcriptional repressor that can specifically bind to the negative cis -acting element of GATA-3 [ 47 ]. In contrast, AtC3H17 in Arabidopsis and IbC3H18 in sweet potato both function as nuclear transcriptional activators [ 37 , 38 ]. Rice Leaf and tiller angle Increased Controller (OsLIC) and Arabidopsis AtC3H14 and AtC3H15/CDM1 can also bind to DNA and show transcriptional activity in yeast [ 21 , 48 ].…”

“…HUA1, the only protein in Arabidopsis that contains six CCCH motifs, has been characterized as an RNA-binding protein and is involved in flower morphogenesis [ 35 , 36 ]. AtC3H17 plays multiple roles in plant development and stress response [ 37 , 38 ]. KHZ1 and KHZ2 could mediate flowering and senescence in Arabidopsis [ 39 , 40 ].…”

A non‐tandem CCCH‐type zinc‐finger protein, IbC3H18, functions as a nuclear transcriptional activator and enhances abiotic stress tolerance in sweet potato

“…Zinc‐finger proteins are divided into different classes according to their numbers and orders of cysteine and histidine residues bound to zinc ions in the secondary structures of the fingers, including C2C2C2C2, C2HCC2C2, C2C2, C2HC, CCCH and C2H2 (Seok et al ., ). Individual finger and spacing structures are normally associated with the specific molecular functions of each zinc‐finger protein (Laity et al ., ).…”