X-gal Assay
X-gal Assay - Related Videos
13:34
Gene Trapping Using Gal4 in Zebrafish
0 Views •
Cited by 19 •
2013
This protocol describes the method of gene trap insertional mutagenesis using Gal4-VP16 as the primary reporter and GFP/RFP as secondary reporters in zebrafish. Approximately one in ten high-expressing F0 fish yield gene trap progeny co-expressing GFP and RFP. The screening procedure can be readily scaled to adapt to the size of the laboratory performing the insertional mutagenesis screen.
06:29
Using the GAL4-UAS System for Functional Genetics in Anopheles gambiae
0 Views •
Cited by 11 •
2021
The bipartite GAL4-UAS system is a versatile tool for modification of gene expression in a controlled spatiotemporal manner which permits functional genetic analysis in Anopheles gambiae. The procedures described for using this system are a semi-standardized cloning strategy, sexing and screening of pupae for fluorescent protein markers and embryo fixation.
05:20
Yeast Two-Hybrid Assay to Determine Protein Self-Association in Yeast Cells
0 Views •
2025
This video demonstrates the yeast two-hybrid assay to detect specific protein self-interactions. In this assay, the protein of interest is tagged to two domains of a transcription factor that encodes the β-galactosidase enzyme. When the two proteins interact, this causes transcription and translation to form the enzyme, which is then detected using a biochemical assay.
08:18
Targeting Olfactory Bulb Neurons Using Combined In Vivo Electroporation and Gal4-Based Enhancer Trap Zebrafish Lines
0 Views •
Cited by 8 •
2011
The temporal and spatial resolution of genetic manipulations determines the spectrum of biological phenomena that they can perturb. Here we use temporally and spatially discrete in vivo electroporation, combined with transgenic lines of zebrafish, to induce expression of a GFP transgene specifically in neurons of the developing olfactory bulb.
08:52
Live Imaging of Innate Immune and Preneoplastic Cell Interactions Using an Inducible Gal4/UAS Expression System in Larval Zebrafish Skin
0 Views •
Cited by 9 •
2015
Studying the earliest events of preneoplastic cell progression and innate immune cell interaction is pivotal to understand and treat cancer. Here we describe a method to conditionally induce epithelial cell transformations and the subsequent live imaging of innate immune cell interaction with HRASG12V expressing skin cells in zebrafish larvae.
FAQs
The key chemical event is cleavage of the colorless X-gal substrate by β-galactosidase. This reaction produces an insoluble blue compound rather than a freely dispersed signal. As a result, blue coloration identifies cells, colonies, or tissue regions where the enzyme is active, allowing researchers to connect visible staining with expression of the lacZ reporter gene.
The lacZ gene serves as a reporter whose β-galactosidase activity can be visualized after exposure to X-gal. When lacZ expression is associated with a promoter under study, blue staining provides a visible readout of promoter activity. This makes the assay useful for examining whether genetic regulatory sequences produce detectable expression in cultured cells or tissues.
The blue product reveals the location of detectable β-galactosidase activity within the sample. Because it is insoluble, the signal can mark individual cells, colonies, or regions of tissue rather than simply indicating activity in a mixed solution. This spatially visible outcome helps researchers determine which parts of a biological sample express the reporter.
A typical workflow begins with a biological sample containing, or suspected of containing, β-galactosidase activity. Researchers expose the sample to X-gal and then inspect it for formation of the blue product. The resulting color pattern is interpreted as evidence of reporter activity, with blue cells, colonies, or tissue regions selected for further analysis.
In bacterial experiments, researchers can use the assay to distinguish colonies associated with lacZ reporter activity. After applying X-gal, colonies that develop blue coloration provide a visible indication of β-galactosidase activity. This supports screening during recombinant work by helping identify bacterial colonies that match the expected reporter-based outcome.
Following plasmid delivery or transfection, the assay can reveal whether cells display activity from a lacZ reporter. Blue staining provides a practical visual readout for cells receiving and expressing the reporter construct. In cultured cells and tissues, researchers can also use the same approach to monitor promoter activity and compare the distribution of expression across a sample.