哺乳动物细胞可调转基因表达合成最小启动子的系统化工程改造
Systematic engineering of synthetic minimal promoters for tunable transgene expression in mammalian cells
研究者系统优化了最小启动子序列、核心元件组成与调控基序序列，提出最小启动子功能的模块化模型：来自不同最小启动子的顺式调控元件可混合、改动、添加或删除，从而产生可预测的表达结果。研究缩短并提升了已知最小启动子的效率，构建出模块化可调最小启动子，并获得长度 7–8 个核苷酸的候选调控元件，与作为额外调控层的人工 5′UTR 组合后可驱动高效转录。该框架旨在拓展合成启动子在新一代应用中的适用范围。
来源：Nucleic Acids Research · doi.org
Fine-tuning transgene levels is crucial in fundamental and applied research. Native promoters are broadly utilized to regulate transgene expression. However, their large size and structural complexity hinder predictable tuning, constrain compatibility with viral vectors with limited capacity, and increase the risk of homologous recombination. Synthetic promoters are short de novo sequences, typically consisting of an enhancer region, which is positioned upstream of a minimal promoter that determines transcription initiation efficiency. Enhancer optimization typically yields coarse activation shifts, alters response curves, and requires case-by-case optimization. Synthetic minimal promoter architecture enables fine-tuning that is potentially compatible with any enhancer region. In this study, we systematically optimized minimal promoter sequences, core element composition, and regulatory motif sequences. Our findings support a modular model of minimal promoter function in which cis-regulatory elements from different minimal promoters can be mixed, altered, added, or deleted to yield predictable expression outcomes. We shortened and thereby enhanced the efficiency of known minimal promoters, engineered modular tunable minimal promoters, and generated candidate regulatory elements spanning 7–8 nucleotides that drive efficient transcription when combined with artificial ${5^{\prime}}$ untranslated regions (5'UTRs) that function as an additional regulatory layer. This framework broadens the utility of synthetic promoters for next-generation applications.