Poulios Stylianos, Tsilimigka Foteini, Mallioura Areti, Pappas Dimitris, Seira Eleftheria, Vlachonasios Konstantinos
Department of Botany, School of Biology, Faculty of Science, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece.
Postgraduate Program Studies "Applications of Biology-Biotechnology, Molecular and Microbial Analysis of Food and Products", School of Biology, Faculty of Science, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece.
Plants (Basel). 2022 Dec 17;11(24):3572. doi: 10.3390/plants11243572.
General Control Non-Derepressible 5 (GCN5) is a histone acetyltransferase that targets multiple genes and is essential for the acetylation of Lysine residues in the N-terminal tail of histone H3 in Arabidopsis. GCN5 interacts with the transcriptional coactivator Alteration/Deficiency in Activation 2b (ADA2b), which enhances its activity functioning in multiprotein complexes, such as the Spt-Ada-Gcn5-Acetyltransferase complex (SAGA). Mutations in and result in pleiotropic phenotypes, including alterations in the growth of roots. Auxin is known to regulate root development by modulating gene expression patterns. Auxin moves polarly during plant growth via the Pin-formed (PIN) auxin efflux transport proteins. The effect of GCN5 and ADA2b on auxin distribution at different stages of early root growth (4 to 7 days post-germination) was studied using the reporter lines and . In wild-type plants, auxin efflux transporter PIN1 expression increases from the fourth to the seventh day of root growth. The PIN1 expression was reduced in the roots of and compared to the wild type. The expression of PIN1 in mutants is confined only to the meristematic zone, specifically in the stele cells, whereas it is almost abolished in the elongation zone. Gene expression analysis showed that genes associated with auxin transport, , and , are downregulated in and mutants relative to the wild type. As a result, auxin accumulation was also reduced in and compared to wild-type roots. Furthermore, acetylation of Lysine 14 of histone H3 (H3K14) was also affected in the promoter and coding region of , and genes during root growth of Arabidopsis in mutants. In conclusion, GCN5 acts as a positive regulator of auxin distribution in early root growth by modulating histone H3 acetylation and the expression of auxin efflux transport genes.
通用控制非阻遏蛋白5（GCN5）是一种组蛋白乙酰转移酶，可作用于多个基因，对拟南芥组蛋白H3 N端尾巴中赖氨酸残基的乙酰化至关重要。GCN5与转录共激活因子激活改变/缺陷2b（ADA2b）相互作用，ADA2b可增强其在多蛋白复合物（如Spt-Ada-Gcn5-乙酰转移酶复合物（SAGA））中的活性。GCN5和ADA2b的突变会导致多效性表型，包括根生长的改变。已知生长素通过调节基因表达模式来调控根的发育。在植物生长过程中，生长素通过PIN形成（PIN）生长素外流转运蛋白进行极性运输。利用报告株系研究了GCN5和ADA2b在根早期生长不同阶段（萌发后4至7天）对生长素分布的影响。在野生型植物中，生长素外流转运蛋白PIN1的表达在根生长的第4天到第7天增加。与野生型相比，GCN5和ADA2b突变体根中PIN1的表达降低。PIN1在GCN5突变体中的表达仅局限于分生区，特别是在中柱细胞中，而在伸长区几乎消失。基因表达分析表明，与生长素运输相关的基因，如AUX1、PIN1和PIN2，在GCN5和ADA2b突变体中相对于野生型下调。因此，与野生型根相比，GCN5和ADA2b突变体中生长素的积累也减少。此外，在拟南芥GCN5突变体根生长过程中，H3、AUX1和PIN1基因的启动子和编码区中组蛋白H3赖氨酸14（H3K14）的乙酰化也受到影响。总之，GCN5通过调节组蛋白H3乙酰化和生长素外流转运基因的表达，在根早期生长中作为生长素分布的正调控因子发挥作用。
