The plant-specific zinc dependent DNA binding PLATZ1 gene (Plant AT-rich sequence- and zinc-binding protein) was first isolated from peas. This family of transcription factor consist of two distantly located N-terminal C-x2-H-x11-C-x2-C-x(4–5)-C- x2-C-x(3–7)-H-x2-H and central C-x2-C-x(10–11)-C-x3-C motifs which are required for both zinc binding and DNA binding. Based on transient luciferase assay, PLATZ1 binds non-specifically to the A/T rich sequence including upstream region of pea GTPase pra2 and the enhancer element of plastocyanin petE genes and is responsible for A/T-rich sequence mediated transcriptional repression (Nagano et al., 2001).

At least 14 PLATZ family members have been identified in maize (Wang et al., 2018). A maize PLATZ protein, FL3 (Floury3) is expressed in endosperm and from Yeast-2-hybrid (Y2H) and biomolecular luciferase complementation results interacts with RNA polymerase III subunit 53 (RPC53) and transcription factor class C 1 (TFC1) and therefore is required for transcription of many tRNA and 5S rRNA since the level of these RNAs was significantly reduced in fl3 mutant endosperm (Li et al., 2017).  Y2H also suggests that seven other PLATZs interacted with both RPC53 and TFC1, whereas three had no protein-protein interaction with these two factors. The other six PLATZs interacted with either RPC53 or TFC1 (Wang et al., 2018).

Arabidopsis PLATZ1 and PLATZ2 play important roles in desiccation tolerance (DT) in seeds and partial DT in vegetative tissues confirmed by knockout mutant and overexpression studies (González-Morales et al., 2016). Gossypium hirsutum, GhPLATZ1 expression is induced in response to NaCl, mannitol osmotic stress and Abscisic (ABA), gibberellin (GA) hormone treatments and ectopic expression of GhPLATZ1 in Arabidopsis resulted in increased insensitivity to osmotic stress and ABA treatment suggesting its role in cotton seed germination and seedling establishment through hormone mediated osmotic stress regulation (Zhang et al., 2018). An Arabidopsis PLATZ TF, Oresara15-1Domonant (ore15-1D) mutant with enlarged leaf size and extended leaf longevity was isolated from activation tagged lines. By regulating GROWTH REGULATING FACTOR (GRF)/GRF-INTERACTING FACTOR pathway, ORE15 increases leaf growth and suppress senescence in Arabidopsis (Kim et al., 2018). On the other hand, based on ore15 mutant and overexpressing lines  it regulates root apical meristem (RAM) size by antagonistically mediating interaction between auxin and cytokinin signaling pathways.  

The quantitative trait locus GL6 in rice positively regulates grain length and number in young panicles and grains by regulating the expression of genes involved in rice grain development through interaction with RPCC53 and TFC1 components of RNA polymerase III complex, where overexpression of GL6 resulted in large grains and null gl6 mutant developed smaller grains (Wang et aal., 2019). The wheat genome consists of 62 TaPLATZs genes distributed unevenly across 15 chromosomes, classified into 6 groups based on phylogenetic analysis. Genome duplication with polyploidization is responsible for expansion of the wheat PLATZ gene family clustered into four modules, where module b exhibits seed specific PLATZ gene expression (Fu et al., 2020). Phyllostachys edulis PLATZ1 improves drought tolerance by enhancing water retention capacity, reducing membrane and oxidative damage and mediating osmotic regulation mostly by ABA signaling pathway (Zhang et al., 2022)

Last updated June 2023 by Ankita Abnave

References:

Nagano Y, Furuhashi H, Inaba T, Sasaki Y. A novel class of plant-specific zinc-dependent DNA-binding protein that binds to A/T-rich DNA sequences. Nucleic Acids Res. 2001 Oct 15;29(20):4097-105. doi: 10.1093/nar/29.20.4097. PMID: 11600698; PMCID: PMC60209.

Li Q, Wang J, Ye J, Zheng X, Xiang X, Li C, Fu M, Wang Q, Zhang Z, Wu Y. The Maize Imprinted Gene Floury3 Encodes a PLATZ Protein Required for tRNA and 5S rRNA Transcription through Interaction with RNA Polymerase III. Plant Cell. 2017 Oct;29(10):2661-2675. doi: 10.1105/tpc.17.00576. Epub 2017 Sep 5. PMID: 28874509; PMCID: PMC5774582.

González-Morales SI, Chávez-Montes RA, Hayano-Kanashiro C, Alejo-Jacuinde G, Rico-Cambron TY, de Folter S, Herrera-Estrella L. Regulatory network analysis reveals novel regulators of seed desiccation tolerance in Arabidopsis thaliana. Proc Natl Acad Sci U S A. 2016 Aug 30;113(35):E5232-41. doi: 10.1073/pnas.1610985113. Epub 2016 Aug 22. PMID: 27551092; PMCID: PMC5024642.

Zhang S, Yang R, Huo Y, Liu S, Yang G, Huang J, Zheng C, Wu C. Expression of cotton PLATZ1 in transgenic Arabidopsis reduces sensitivity to osmotic and salt stress for germination and seedling establishment associated with modification of the abscisic acid, gibberellin, and ethylene signalling pathways. BMC Plant Biol. 2018 Oct 4;18(1):218. doi: 10.1186/s12870-018-1416-0. PMID: 30286716; PMCID: PMC6172764.

Kim JH, Kim J, Jun SE, Park S, Timilsina R, Kwon DS, Kim Y, Park SJ, Hwang JY, Nam HG, Kim GT, Woo HR. ORESARA15, a PLATZ transcription factor, mediates leaf growth and senescence in Arabidopsis. New Phytol. 2018 Oct;220(2):609-623. doi: 10.1111/nph.15291. Epub 2018 Jun 27. PMID: 29949656.

Wang A, Hou Q, Si L, Huang X, Luo J, Lu D, Zhu J, Shangguan Y, Miao J, Xie Y, Wang Y, Zhao Q, Feng Q, Zhou C, Li Y, Fan D, Lu Y, Tian Q, Wang Z, Han B. The PLATZ Transcription Factor GL6 Affects Grain Length and Number in Rice. Plant Physiol. 2019 Aug;180(4):2077-2090. doi: 10.1104/pp.18.01574. Epub 2019 May 28. PMID: 31138620; PMCID: PMC6670106.

Fu Y, Cheng M, Li M, Guo X, Wu Y, Wang J. Identification and Characterization of PLATZ Transcription Factors in Wheat. Int J Mol Sci. 2020 Nov 25;21(23):8934. doi: 10.3390/ijms21238934. PMID: 33255649; PMCID: PMC7728089.

Zhang K, Lan Y, Wu M, Wang L, Liu H, Xiang Y. PhePLATZ1, a PLATZ transcription factor in moso bamboo (Phyllostachys edulis), improves drought resistance of transgenic Arabidopsis thaliana. Plant Physiol Biochem. 2022 Sep 1;186:121-134. doi: 10.1016/j.plaphy.2022.07.004. Epub 2022 Jul 8. PMID: 35835078.

Wang J, Ji C, Li Q, Zhou Y, Wu Y. Genome-wide analysis of the plant-specific PLATZ proteins in maize and identification of their general role in interaction with RNA polymerase III complex. BMC Plant Biol. 2018 Oct 5;18(1):221. doi: 10.1186/s12870-018-1443-x. PMID: 30290770; PMCID: PMC6173924.