How they suppress your genes so they can express the synthetic ones for they synthetic gene networks 👇👇👇👇 Mechanism for Suppressing Real Genes Suppression of endogenous genes is typically achieved through targeted interference, which prevents the cell's natural machinery from transcribing or translating them. sciencedirect.com/science/ch… Methods of suppressing genes CRISPR Interference (CRISPRi): A catalytically "dead" Cas9 (dCas9) protein is guided by a synthetic RNA to a specific location on the real gene's promoter. Instead of cutting the DNA, it sits there as a physical "roadblock," preventing RNA polymerase from binding and starting transcription. RNA Interference (RNAi): Synthetic small interfering RNAs (siRNAs) or short hairpin RNAs (shRNAs) are introduced to bind complementarily to the messenger RNA (mRNA) of the real gene. This triggers the cell's internal "antiviral" response to degrade that specific mRNA before it can be used to make proteins. Transcriptional Repressors: Synthetic networks can produce repressor proteins (like LacI or TetR) designed to bind to specific "operator" sites inserted near the real gene's promoter, physically blocking transcription Image two—PLUG-AND-PLAY METHODOLOGY FOR SYNTHETIC GENE NETWORKS (a) Elements comprising the framework: parental cloning vectors harboring a custom multiple cloning site (MCS) of optimal restriction enzyme sites; a library of commonly-used synthetic genetic components designed to exclude the restriction sites; a repository of assembled constructs that includes synthetic modules, intermediates, and circuits. (b) Generalized workflow for constructing and modifying synthetic gene networks, which prioritizes and streamlines the iterative process of arriving at functional networks and modules. pmc.ncbi.nlm.nih.gov/article… Positive regulatory interactions are encoded by T7 and SP6 phage RNA polymerases (RNAPs), which start transcription at T7 or SP6 promoters, respectively. Negative interactions are encoded by the transcriptional repressors LacI (lactose operon repressor protein) & TetR (tetracycline repressor). They inhibit transcription when bound to their operator sites (LacO, TetO), which are placed downstream of promoters. The two networks employ distinct mechanisms to produce a gene expression stripe pattern. link.springer.com/article/10… Mechanism for Expressing Synthetic Genes Expressing synthetic genes requires ensuring they are recognized by the cell as high-priority instructions, often using orthogonal (independent) control systems. Synthetic RNA-based post-transcriptional expression control methods & genetic circuits RNA-based synthetic genetic circuits provide an alternative for traditional transcription-based circuits in applications where genomic integration is to be avoided. Incorporating various post-transcriptional control methods into such circuits allows for controlling the behaviour of the circuit thru the detection of certain biomolecular inputs or reconstituting defined circuit behaviours, thus manipulating cellular functions.  sciencedirect.com/science/ar… A Computational Modeling Approach for the Design of Genetic Control Systems that Respond to Transcriptional Activity link.springer.com/protocol/1… Orthogonal Promoters: Synthetic genes are paired with promoters that the host cell's standard transcription factors do not recognize. They only turn "on" when a specific synthetic activator or chemical inducer (like IPTG or aTc) is present. Genetic Code Expansion: Synthetic nucleic acids can include "unnatural" base pairs or codons that require specialized synthetic tRNAs to be read, allowing the cell to produce entirely new proteins that natural genes cannot code for. Riboregulators: Some synthetic networks use RNA-based switches where the synthetic gene's mRNA is "locked" in a shape that hides its ribosome-binding site. It only becomes "expressible" when a specific synthetic trigger RNA binds to it & unfolds the structure nature.com/articles/s41467-0…

Look at this Sal. Phage-derived CasΦ uses a single active site to process guide RNA and cut DNA for genome editing and nucleic acid detection. pmc.ncbi.nlm.nih.gov/article…

4D Applications A 4D bio-Kirigami approach Four-dimensional (4D) hydrogel systems have emerged as a promising strategy for engineering dynamically reconfigurable tissue architectures. These systems typically consist of initially simple structures, such as strips, sheets, or discs, that undergo programmed shape transformations in response to external stimuli, forming complex architectures with continuous curvature variations. Incorporating live cells into these hydrogels and culturing them in tissue-specific environments enables the generation of dynamic curved tissues that are challenging to achieve using conventional or 3D bioprinting-based tissue engineering approaches. In this context, we introduce a bio-Kirigami strategy that allows cell-laden biomaterials to gradually transform from simple designs into complex 3D architectures during the culture process. By spatially integrating hydrogels with different swelling and degradation behaviors, this system generates programmable and continuously evolving curvatures while supporting long-term cell viability and tissue formation. The bio-Kirigami construct was fabricated using a multi-step photolithographic polymerization approach. The outer ring was composed of an interpenetrating polymer network (IPN) hydrogel formed by calcium ion (Ca2+)-crosslinked alginate and photocrosslinked poly(ethylene glycol) diacrylate (PEG-DA) (ALG-PEG), while the inner bars were fabricated using a hydrogel blend consisting of oxidized and methacrylated alginate (OMA) and gelatin methacrylate (GelMA) (OMAGM). The chemical structures of OMA, PEG-DA, and GelMA were confirmed via ¹H nuclear magnetic resonance (NMR) analysis Bio-Kirigami-based 4D Morphogenetic Tissue Engineering Human mesenchymal stem cells (hMSCs) were encapsulated within the inner components of the “single dome” construct and divided into two groups: control constructs (Ctrl), which were cultured in standard cell expansion medium, and differentiation constructs (CPM), which were cultured in chondrogenesis-pellet medium. Throughout the culture period, both groups exhibited continuous morphing into dome-like configurations with progressively increasing deformation heights. The results revealed that the Ctrl constructs gradually collapsed in the absence of the structural constraints of the outer ring, whereas the CPM constructs maintained their architecture and structural integrity, showing minimal visible and quantitative changes. This stability in the CPM group was attributed to the substantial accumulation of ECM, which provided mechanical support and prevented structural collapse post-excision. cell.com/cell-biomaterials/f…