Jul 2026· New Biotechnology· Vol 95, pp. 25-34· 0 citations· 42 references
Medicine
Abstract
Precise spatial restriction of transgene expression is essential for safe in vivo production of bioactive proteins; however, regulatory elements that confer tissue specificity often span large genomic regions and are incompatible with size-limited viral vectors. Here, we report a compact synthetic promoter-feedback circuit that enables enhanced, oviduct-restricted transgene expression in chickens. By combining a minimal ovalbumin promoter (<200bp) with a tetracycline-responsive element (TRE)-tTA positive feedback loop, we established a viral vector-compatible expression module that achieves enhanced transcriptional output while preserving tissue specificity. This system was validated in vitro and in genetically modified chickens. As a functional demonstration, chickens expressing transforming growth factor beta 1 (TGF-β1) specifically in egg white were generated. TGF-β1 accumulated predominantly as a presumptive latent/pro-form consisting of the latency-associated peptide (LAP)/pro-domain and the mature TGF-β1 dimer, at a semi-quantitatively estimated level of approximately 110µg/mL, and remained detectable for over 2 years. Oral administration of TGF-β1-containing egg white significantly attenuated inflammation in a murine DSS-induced colitis model. Together, these findings establish a modular, size-efficient transcriptional enhancement platform that enables robust tissue-restricted expression in vivo. This strategy provides a generalizable framework for overcoming regulatory size constraints in viral vector-mediated gene delivery and expands the potential for producing edible biopharmaceuticals in transgenic livestock.
The first isolation and characterization of the buffalo EF1α1 promoter is reported, demonstrating its strong gene expression activity both in vitro across diverse cultured cell types and in vivo across multiple mouse organs, establishing the bbEF1α1 promoter as a powerful ubiquitous driver of gene expression.
Findings establish COMPACTs as a practical alternative to native promoters for various applications, including cell therapies, gene therapies, and biomanufacturing.
Chaja Katzman, S. Matusevich, Shir-Liya Dadon et al.· bioRxiv· 0 citations
Background: Small-molecule-regulated gene switches are important tools for programmable mammalian cell engineering, and compact switches responsive to clinically familiar ligands that can be administered locally are particularly attractive for externally regulated transgene expression. Methods: Here, we developed ZF10–ΔVDR, a compact zinc-finger–VDR transcriptional switch, by fusing an orthogonal human-derived zinc-finger array, ZF10, to the hinge and ligand-binding domain of the vitamin D receptor. The resulting switch enabled transgene regulation by calcipotriol, a clinically used topical vitamin D analog and VDR agonist. Results: ZF10–ΔVDR maintained low basal activity, showed limited activation by the tested vitamin D species at physiologically relevant reference concentrations, and was robustly activated by calcipotriol. The system functioned across multiple human cell types. In vivo, topical calcipotriol increased serum reporter output in mice bearing subcutaneous microencapsulated-cell implants, whereas oral vitamin D3 did not measurably activate this system under the tested conditions. In a separate HaCaT implantation model, topical calcipotriol increased bioluminescence at wound-adjacent implantation sites. ZF10–ΔVDR also supported reversible ON/OFF cycling under the tested conditions and inducible secreted protein output in vitro. Conclusions: These findings establish ZF10–ΔVDR as a calcipotriol-responsive switch with limited activation by endogenous vitamin D species, activity across multiple mammalian cell types, reversible regulation under the tested conditions, and compatibility with topical induction in vivo.
Hong Su, Shi-Ting Li, Guan-Yang Chen et al.· Genes· 0 citations
This review systematically summarizes the features of Bacillus subtilis expression systems, the regulatory effects of various promoters on heterologous expression efficiency, and rational modification strategies of promoter core regions, offering valuable references for the rational development of high-efficiency promoter engineering strategies and heterologous gene expression optimization.
Man-Fei Li, Meng Zheng, Peng-Yuan Wang et al.· Journal of Microbiological M...· 0 citations
This work cloned the promoter of the housekeeping gene eukaryotic translation elongation factor 1α (EF1Α, AAEL017096) and confirmed its transcriptional activity, and truncated the U6 promoter, expanding the genetic toolkit for Ae.
