DOF transcription factors: Specific regulators of plant biological processes

Abstract

Plant biological processes, such as growth and metabolism, hormone signal transduction, and stress responses, are affected by gene transcriptional regulation. As gene expression regulators, transcription factors activate or inhibit target gene transcription by directly binding to downstream promoter elements. DOF (DNA binding with One Finger) is a classic transcription factor family exclusive to plants that is characterized by its single zinc finger structure. With breakthroughs in taxonomic studies of different species in recent years, many DOF members have been reported to play vital roles throughout the plant life cycle. They are not only involved in regulating hormone signals and various biotic or abiotic stress responses but are also reported to regulate many plant biological processes, such as dormancy, tissue differentiation, carbon and nitrogen assimilation, and carbohydrate metabolism. Nevertheless, some outstanding issues remain. This article mainly reviews the origin and evolution, protein structure, and functions of DOF members reported in studies published in many fields to clarify the direction for future research on DOF transcription factors.

Keywords: DOF; metabolic regulation; plant hormones; transcription factor; zinc finger.

Figure 1

Schematic representation of the DOF transcription factor structure. The DOF zinc finger domain, nuclear localization signal, and transcriptional activation domain are shown in blue, green, and yellow, respectively. The amino acid sequence in the zinc finger domain of DOF is represented by abbreviations, the zinc coordination is shown in bright green, the position of the four cysteines in the zinc finger structure is shown in red, the question mark represents any amino acid, and the tryptophan residue mentioned in the second part is shown in purple.

Figure 2

DOFs promote plant tolerance under different abiotic stresses. The DOF family members are represented in red, and the box marks resistance to different stresses. The blue, green, yellow, grey, and orange boxes represent cold tolerance, drought tolerance, salt tolerance, osmotic tolerance, and heat tolerance, respectively. The black arrows indicate facilitated relationships. AsA, ascorbic acid.

Figure 3

A network model of DOF members participating in different phytohormone pathways. A total of 8 hormone modules are distributed. DOF members are shown in red. Positive and negative regulatory relationships are represented by black arrows and blunted lines, respectively.

Figure 4

Model of DOFs involved in the regulation of plant metabolism. The blue, yellow, grey, and green modules represent carbon and nitrogen assimilation, carbohydrate metabolism, fatty acid metabolism, and phenylpropanoid metabolism, respectively. Red indicates DOF members in different plants. Dotted lines indicate that some processes have been omitted. NR/NiR, nitrate/nitrite reductases; AMTs, ammonium transporters; GS, glutamine synthetase; GOGAT, glutamate synthase; Fru-6-P, fructose-6-phosphate.