New Molecular Interaction Technology: How Much Do You Know About Yeast Hybridization Technology?-Antibody Detection Service Topic-Tekbiotech-Yeast and Phage Display CRO, Expert in Nano-body and Antibody Drug Development

New Molecular Interaction Technology: How Much Do You Know About Yeast Hybridization Technology?

In a living system, nearly all life processes are regulated by proteins. They modulate gene expression, catalyze chemical reactions, transport small molecules across membranes, and transmit signals across membranes. Yeast hybridization is an important technology for studying these mechanisms.

This necessitates mentioning the key player in yeast hybridization technology: the GAL4 transcriptional activator, which can be considered the cornerstone of this technology. GAL4 contains two critical domains: the DNA-Binding Domain (BD) and the Activation Domain (AD). When the BD and AD are brought together, the transcription of downstream genes is initiated ^[1].

The Yeast Two-Hybrid (Nuclear) System

The yeast two-hybrid system detects protein-protein interactions by fully exploiting the two domains of GAL4, treating them as separable components. As shown in Figure 1, two fusion proteins are first constructed. An exogenous protein X, termed the bait protein, is fused to the BD vector to generate a plasmid. Protein Y, termed the prey protein, is fused to the AD vector. The BD and AD exist separately as fusion partners. These two fusion plasmids are co-transfected into yeast cells. If X and Y do not interact, they remain at a spatial distance within the yeast cell, and consequently, downstream transcriptional genes (i.e., reporter genes) are not activated (Figure 1A). If these two proteins interact, bringing them into close proximity for specific binding, then the BD recognizes and binds to the Upstream Activating Sequence (UAS), enabling the AD to initiate transcription of downstream genes. For ease of screening and manipulation, reporter genes are typically integrated into the yeast genome. Commonly used reporter genes include auxotrophic markers such as HIS3, ADE2, and LEU2, as well as the colorimetric reporter gene lacZ (encoding β-galactosidase). If a reporter gene is activated, colonies will grow or turn blue, making them easy to observe.

Figure 1: Schematic diagram of the yeast two-hybrid (nuclear) system ^[2].

The Yeast Two-Hybrid Membrane System

Of course, the yeast two-hybrid interaction occurs within the nucleus, which may not be applicable for proteins that function in other cellular compartments, such as the cell membrane or cytoplasm. The yeast two-hybrid membrane system can overcome this limitation. This system primarily utilizes ubiquitin, a key characteristic of which is its ability to reassemble even when split into two halves (the N-terminal Nub and the C-terminal Cub), provided they are brought into close spatial proximity. Leveraging this characteristic, scientists have modified Nub into NubG, which cannot spontaneously reassociate with Cub. Additionally, a complete transcription factor (commonly a TF transcription factor) is linked to Cub. Furthermore, NubG is fused to a bait (known protein), while the Cub-TF fusion is linked to a prey (unknown protein). If the two proteins interact, NubG and Cub reassemble into intact ubiquitin, which is recognized and cleaved by ubiquitin-specific proteases, releasing the transcription factor.

Figure 2: Schematic diagram of the yeast two-hybrid membrane system ^[3].

Table 1: Key Differences Between the Membrane System and the Traditional

The Yeast One-Hybrid System

The yeast one-hybrid system detects interactions between DNA and proteins. In summary, a known DNA sequence is integrated into the yeast genome. An unknown protein Y is fused to an AD vector. If protein Y interacts with the DNA, the AD activates transcription of the reporter gene.

Figure 3: Schematic diagram of the yeast one-hybrid system.

TekBiotech has established a comprehensive yeast hybridization technology platform. We are dedicated to providing scientists worldwide with high-quality protein interaction analysis services, including experimental design, library screening, bait vector construction, yeast two-hybrid/one-hybrid system optimization, and downstream interaction validation and data analysis (such as co-immunoprecipitation and luciferase reporter gene assays). By offering one-stop solutions, we provide robust support for our clients' research projects.

References

[1] Duarte CEM, Eucylides NC. Protein-Protein Interaction via Two-Hybrid Assay in Yeast. Methods Mol Biol. 2024;2724:193-210.
[2] Farooq QUA, Shaukat Z, Aiman S, Li CH. Protein-protein interactions: Methods, databases, and applications in virus-host study. World J Virol. 2021 Nov 25;10(6):288-300.
[3] Gisler SM, Kittanakom S, Fuster D, et al. Monitoring protein-protein interactions between the mammalian integral membrane proteins using the split-ubiquitin membrane-based yeast two-hybrid system. *This citation appears incomplete in the original. Based on context, the likely full reference is: Gisler SM, Kittanakom S, Fuster D, et al. Monitoring protein-protein interactions between the mammalian integral membrane proteins using the split-ubiquitin membrane-based yeast two-hybrid system. Mol Cell Proteomics. 2008;7(7):1362-77.*

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