Understanding Yeast One Hybrid Assay and Its Applications

What is Yeast One Hybrid?

The yeast one hybrid (Y1H) assay is a genetic tool of considerable potency and utility, employed to discern the interactions between proteins and DNA within a live system. The assay operates through the joint deployment of a reporter gene and a bait DNA sequence positioned upstream of the former. The bait sequence is fused to a DNA-binding domain of a transcription factor, which is subsequently transported into yeast cells. Upon binding to the bait sequence, the transcription factor activates the reporter gene, thus generating a measurable signal.

Given its ability to identify proteins that bind to specific DNA sequences, the Y1H assay yields insights of great value into regulating gene expression, transcriptional control, and cellular signaling pathways. Moreover, it is a crucial technique used to investigate the function of transcription factors, as well as the impact of mutations on protein-DNA interactions.

Understanding Yeast One Hybrid Assay and Its Applications

Yeast One Hybrid Assay Protocol

Here is a basic protocol for performing a Y1H assay:

  • Clone the DNA-binding domain of a transcription factor into a plasmid vector.
  • Clone the bait sequence upstream of a reporter gene in another plasmid vector.
  • Introduce both plasmid vectors into yeast cells (either by transformation or electroporation).
  • Plate the yeast cells on selective media that only allows for the growth of cells with the bait and reporter plasmids.
  • Monitor the growth of the yeast cells and assay for reporter gene expression.

The specific details of the Y1H assay protocol can vary depending on the research question and the type of interaction being studied. For example, a Y1H screen protocol will involve the use of a library of potential interacting proteins.

What is Yeast One Hybrid Used for?

Y1H assays have a wide range of applications in biological research. They are commonly used to identify protein-DNA interactions, but can also be used for the following:

  • Study the function of transcription factors and the regulation of gene expression.
  • Identify cofactors and other regulatory proteins that interact with transcription factors.
  • Study protein-protein interactions by fusing the DNA-binding domain to a protein of interest and using the bait sequence to target a protein complex.
  • Screen for small molecules that disrupt protein-DNA interactions, which can lead to the development of novel drugs.

Reversed yeast-1-hybrid program for tad identificationReversed yeast-1-hybrid program for tad identification (Dalton et al., 2016).

What is the Difference between Yeast One Hybrid and Yeast Two-Hybrid?

In the vast and intricate realm of genetics, there exists a tool of great power: Y2H. This magnificent screening tool can identify protein-protein interactions within a living organism, thus opening up a whole new world of possibilities for biological research. It stands apart from its counterpart, Y1H, which is specifically used for identifying protein-DNA interactions.

Now, let's delve deeper into the intricacies of Y2H. Within this system, there exists a bait protein that is fused to the DNA-binding domain of a transcription factor. Conversely, there is also a prey protein that is fused to the activation domain. Should these two proteins interact, they will bring about the convergence of the DNA-binding and activation domains, ultimately leading to the activation of the reporter gene. The uses for Y2H assays are vast and varied, as they are frequently employed in the identification of protein-protein interactions, the study of signal transduction pathways, and the investigation of protein function.

It is important to note that both Y1H and Y2H assays have their unique strengths and weaknesses. The choice between them ultimately rests on the nature of the specific research question and the type of interaction being studied. With such powerful tools at our disposal, the possibilities for genetic research are truly endless.


  1. Dalton, Jutta C., et al. "A modified reverse one-hybrid screen identifies transcriptional activation domains in PHYTOCHROME-INTERACTING FACTOR 3." Frontiers in plant science 7 (2016): 881.
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