The effects of transcription directions of transgenes and the gypsy insulators on the transcript levels of transgenes in transgenic arabidopsis

Authors: JAING, WEIJIA - Sichuan University; SUN, LI - Texas Tech University; YANG, XIAOJIE - Henan Agricultural University; WANG, MAOHUA - Sichuan University; ESMAEILI, NARDANA - Texas Tech University; PEHLIVAN, NECLA - Recep Tayyip Erdogan University; ZHAO, RONGLI - Chengdu Institute; ZHANG, HONG - Texas Tech University; ZHAO, YUN - Sichuan University

Submitted to: Nature Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/19/2017
Publication Date: 11/7/2017
Citation: Jaing, W., Sun, L., Yang, X., Wang, M., Esmaeili, N., Pehlivan, N., Zhao, R., Zhang, H., Zhao, Y. 2017. The effects of transcription directions of transgenes and the gypsy insulators on the transcript levels of transgenes in transgenic arabidopsis. Nature Scientific Reports. 7:14757. https://doi.org/10.1038/s41598-017-15284-x.
DOI: https://doi.org/10.1038/s41598-017-15284-x

Interpretive Summary: As available water from the Ogallala Aquifer for irrigation decreases, farmers will seek crop varieties that are more water efficient. Conventional plant breeding methods have increased the yield potential of many commonly grown crops including cotton, wheat and corn. Traditional breeding methods tend to increase crop yields in a progressive, incremental manner. However, transgenetic technologies may increase crop water use by a rapid leap forward. A gene from fruit flies may increase the expression of introduced genes in transgenetic plants. Therefore, scientists from Texas Tech University, Chengdu Institute of Biological Products Co. (China), Henan Academy of Agricultural Sciences (China), Recep Tayyip Erdogan University (Turkey) and Sichuan University (China) in the ARS led Ogallala Aquifer Program examined the effects of this fruit fly gene on the expression of two plant genes introduced into a model plant. The results showed that the fruit fly gene does promote the expression of two genes in transgenic plants.

Technical Abstract: Manipulation of a single abiotic stress-related gene could improve plant performance under abiotic stress conditions. To simultaneously increase plant tolerance to multiple stresses, it is usually required to overexpress two (or more) genes in transgenic plants. The common strategy is to assemble two or more expression cassettes, where each gene has its own promoter and terminator, within the same T-DNA. Does the arrangement of the two expression cassettes affect expression of the two transgenes? Can we use the Drosophila gypsy insulator sequence to increase the expression of the two transgenes? Answers to these questions would contribute to design better transformation vectors to maximize the effects of multi-gene transformation. Two Arabidopsis genes, PP2A-C5 and AVP1, and the gypsy insulator sequence were used to construct six transformation vectors with or without the gypsy insulator bracketing the two expression cassettes: uni-directional transcription, divergent transcription, and convergent transcription. Total RNAs were isolated for reverse transcription- quantitative realtime polymerase chain reaction (RT-qPCR) assays and a thorough statistical analysis was conducted for the RT-qPCR data. The results showed that the gypsy insulator does promote the expression of two transgenes in transgenic plants. Besides, the plants containing the divergent transcription cassettes tend to have more correlated expression of both genes.