Characterization Analysis and Responses to NaCl and H2O2 Stress of AtTERT in Arabidopsis thaliana
WANG Yang1, SUN Yu-Ping1, DONG Qi1, YANG Ying1, LIU Ying1, YU Ting-Qiao2, WU Xiao-Fei2, LU Cun-Fu1, *
1 Beijing Advanced Innovation Center for Tree Breeding by Molecular Design/National Engineering Laboratory for Tree Breeding/College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, China; 2 School of Life Sciences, Peking University, Beijing 100871, China
Abstract：Telomerase is a ribonucleoprotein complex with reverse transcriptase activity in eukaryotic cells, telomerase reverse transcriptase (TERT) is the major component of telomerase. AtTERT is the first plant telomerase reverse transcriptase TERT gene cloned from Arabidopsis thaliana. In order to clarify the structure and function of AtTERT, bioinformatics tools and software were used to analyze the physicochemical properties, protein structure and functional domain of AtTERT, and the genetic relationship of TERT genes among different species. Moreover, the telomerase activity and AtTERT gene expression patterns under salt and oxidative stress were analyzed. The results showed that the AtTERT belonged to a hydrophilic protein without a signal peptide, and had no obvious transmembrane domain. There were 125 phosphorylation sites, of which 87, 28 and 10 were serine, threonine and tyrosine sites, respectively. Irregular crimps and α-helices were the major structural elements of secondary structure of AtTERT. Conserved domains were the TRBD (telomerase RNA binding motif) domain and the RT (telomerase reverse transcriptase motifs) domain. Three-dimensional structure modeling analysis revealed a 74% similarity of the main-chain conformation between AtTERT and the Tetrahymena thermophila telomerase reverse transcriptase c6d6vA. Phylogenetic analysis using the TERT protein sequences of Gramineae, Leguminosae, Liliaceae, Rosaceae, etc, revealed that TERT was highly conserved in the same plant group. For example, TERT was highly conserved in the branches of Prunus mume and P. persica (bootstrap>99), and they had a confidence index cluster of 100, and all of the above belonged to Rosaceae. The phylogentic tree constructed by TERT conforms the right phylogenetic relationships of the plant species. Leguminous plants such as Glycine max, Phaseolus vulgaris and Solanaceae plants such as Solanum lycopersicum, S. tuberosum, Nicotiana tabacum also reflected a similar situation. Furthermore, intron and exon sequence analysis was carried out using the TERT sequences from different families. It was found that the number of exons and introns of TERT from different plants were different. Functional network prediction indicated that AtTERT might interact with some important functional proteins such as the non-homologous end-joining protein 70 (Ku70), Ku80, telomerase protective protein 1a of Arabidopsis thaliana (AtPOT1a), TER1, nucleolar protein (NAP57), recombinant DNA repair protein 50 (RAD50) and suppressor with morphogenetic effect on genitalia 7 (SMG7), which involved in telomere repair or non-telomere functions. To reveal the potential non-telomere function of AtTERT, telomerase activity and AtTERT expression pattern were detected simultaneously during salt and H2O2 treatment. At 3 d of 200 mmol/L NaCl treatment, telomerase activity increased obviously. However, the telomerase activity decreased at the 7 d. Accordingly, the Arabidopsis seedlings had been whitened at the 7 d. Further, the telomerase activity increased when treated with 0.4 mmol/L H2O2, and decreased with the further increase of H2O2 concentration from 0.8 mmol/L to 2.0 mmol/L. The AtTERT expression also increased first and then decreased under salt and oxidative stress. In summary, the present research results indicated that TERT genes are highly conserved in the same group of plants. Telomerase might have non-telomeric functions, such as regulation of gene expression, and cell repair in response to abiotic stress. The results provide new reference data for further study of plant TERT structure and function.
王杨, 孙玉萍, 董琦, 杨颖, 刘颖, 于婷乔, 吴晓飞, 卢存福. 拟南芥AtTERT基因特性分析及其对盐与过氧化氢胁迫的响应[J]. 农业生物技术学报, 2019, 27(4): 581-592.
WANG Yang, SUN Yu-Ping, DONG Qi, YANG Ying, LIU Ying, YU Ting-Qiao, WU Xiao-Fei, LU Cun-Fu. Characterization Analysis and Responses to NaCl and H2O2 Stress of AtTERT in Arabidopsis thaliana. 农业生物技术学报, 2019, 27(4): 581-592.
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