State transitions are an acclimatory response by which plants, algae, and cyanobacteria counteract photosynthetic inefficiency caused by changes in incident light quality. In plants and green algae, state transition 7 (STN7/STT7) kinase promotes state 2 transition. Conserved cysteine residues are implicated in STN7/STT7 regulation, but the precise nature of their involvement remains unclear. Here, an analysis of the STN7 thiols in vitro and a determination of their midpoint redox potential indicate that the lumenal disulfide linkage is unlikely to be redox regulated while the stromal cysteines form a regulatory intramolecular disulfide. We further show that thioredoxin f 1 (Trx‐ f 1) reduces the STN7 stromal disulfide linkage as consistent with a Trx‐ f 1‐mediated inhibition of the kinase under high light.

Background/Objectives: Transgene applications, ranging from gene therapy to the development of stable cell lines and organisms, rely on maintaining the expression of transgenes. To date, the use of plasmid-based transgenes has been limited by the loss of their expression shortly after their delivery into the target cells. The short-lived expression of plasmid-based transgenes has been largely attributed to host-cell-mediated degradation and/or silencing of transgenes. The development of chromatin-based strategies for gene delivery has the potential to facilitate defining the requirements for establishing epigenetic states and to enhance transgene expression for numerous applications. Methods: To assess the impact of “priming” plasmid-based transgenes to adopt accessible chromatin states to promote gene expression, nucleosome positioning elements were introduced at promoters of transgenes, and vectors were pre-assembled into nucleosomes containing unmodified histones or mutants mimicking constitutively acetylated states at residues 9 and 14 of histone H3 or residue 16 of histone H4 prior to their introduction into cells, then the transgene expression was monitored over time. Results: DNA sequences capable of positioning nucleosomes could positively impact the expression of adjacent transgenes in a distance-dependent manner in the absence of their pre-assembly into chromatin. Intriguingly, the pre-assembly of plasmids into chromatin facilitated the prolonged expression of transgenes relative to plasmids that were not pre-packaged into chromatin. Interactions between pre-assembled chromatin states and nucleosome positioning-derived effects on expression were also assessed and, generally, nucleosome positioning played the predominant role in influencing gene expression relative to priming with hyperacetylated chromatin states. Conclusions: Strategies incorporating nucleosome positioning elements and the pre-assembly of plasmids into chromatin prior to nuclear delivery can modulate the expression of plasmid-based transgenes.

Transgene applications ranging from gene therapy to development of stable cell lines and organisms rely on maintaining expression of transgenes. To-date, the use of plasmid-based transgenes has been limited by loss of their expression shortly after delivery into target cells. This short-lived expression of plasmid-based transgenes has been largely attributed to host cell-mediated degradation and/or silencing of transgenes. To assess the impact of “priming” plasmid-based transgenes to adopt accessible chromatin states to promote gene expression, nucleosome positioning elements were introduced at promoters of transgenes, or vectors were pre-assembled into nucleosomes containing unmodified histones or histone mutants mimicking constitutively acetylated states at residues 9 and 14 of histone H3 or residue 16 of histone H4 prior to their introduction into cells, then transgene expression was monitored over time. DNA sequences capable of positioning nucleosomes could positively impact expression of adjacent transgenes in a distance-dependent manner in the absence of pre-assembly into chromatin. Intriguingly, pre-assembly of plasmids into chromatin facilitated prolonged expression of transgenes relative to plasmids that were not pre-packaged into chromatin. Interactions between pre-assembled chromatin states and nucleosome positioning-derived effects on expression of reporter genes were also assessed and, generally, nucleosome positioning played the predominant role in influencing gene expression relative to priming with hyperacetylated chromatin states.

The past decade has witnessed significant expansion in both preclinical and approved receptor-targeted therapeutic cell modalities. These include immune cells engineered to express chimeric antigen receptors (CARs), and bispecific immune cell engagers developed for the treatment of cancer, autoimmune disorders, infectious diseases, and metabolic disorders. Although these approaches have produced remarkable clinical outcomes, cell therapy-associated off-target toxicities continue to present significant safety challenges. This review provides a framework for the rational design of optimized cell therapies aimed at enhancing therapeutic efficacy while minimizing adverse side effects. With the state-of-the-art advances in genomic profiling, artificial intelligence-driven design tools, and scalable manufacturing technologies, the outlook for next-generation receptor-targeted cell therapies is highly promising.