Final answer:
The yeast two-hybrid system is a method used to test for protein-protein interactions using the mating signal mechanism of Saccharomyces cerevisiae. Proteins are fused to either a DNA-binding or activator domain of a split transcription factor. Interaction between the proteins reconstitutes the transcription factor, activating a reporter gene and indicating interaction.
Step-by-step explanation:
Yeast Two-Hybrid System Definition
The yeast two-hybrid system is a molecular biology technique used to discover protein-protein interactions by exploiting the signaling mechanisms of yeasts, specifically Saccharomyces cerevisiae. This method utilizes a transcription factor that is split into two separate domains: a DNA-binding domain (BD) and an activator domain (AD). The 'bait' protein is fused to the DB, and the 'prey' protein is fused to the AD. If bait and prey proteins interact, the BD and AD come together to initiate transcription of a reporter gene, indicating a positive interaction.
Yeasts, being eukaryotic organisms, share signaling components and processes similar to those found in multicellular organisms, including the use of protein kinases and GTP-binding proteins. They participate in a form of sexual reproduction where haploid cells secrete mating factor to find compatible partners, leading to diploid cells after mating—a process that the yeast two-hybrid system mimics for its functional basis.
In research, this system is invaluable for identifying and analyzing protein interactions that are crucial for understanding cellular functions and signaling pathways. By attaching different proteins to the binding and activating domains of the transcription factor, researchers can determine if those proteins interact based on the expression of the reporter gene.