GUS histochemical assays

Service Introduction

A promoter is a DNA sequence located upstream of the 5’ end of a gene. It guides the correct binding of RNA polymerase to DNA, activates RNA polymerase, recruits the corresponding transcription factors to form a specific transcription initiation complex, and thus determines the direction and efficiency of transcription. It is an important cis-regulatory element in gene expression regulation. The expression pattern and strength of a promoter can only be detected using reporter genes. Currently, a commonly used reporter gene in plant promoter studies is the β-glucuronidase (GUS) gene. The GUS gene encodes β-glucuronidase, a hydrolase, which under suitable conditions can hydrolyze 5-bromo-4-chloro-3-indolyl-β-D-glucuronic acid (X-Gluc) to produce a blue product. At the same time, GUS can react with the substrate 4-methylumbelliferyl-β-D-glucuronide (MUG, molecular weight 352.3) to produce the fluorescent substance 4-methylumbelliferone (MU, molecular weight 198.2). MU has an excitation wavelength of 365 nm and an emission wavelength of 456 nm, and its content can be measured using a microplate reader. Therefore, we can quantitatively detect the GUS content based on the amount of fluorescent substance produced per unit time per unit mass of total plant protein.

Service Advantages

▶Years of experience in sample processing and staining, effectively ensuring clear staining signals and low background interference;

▶Optimized staining and quantification systems, effectively ensuring accurate localization of tissue/cell staining and reproducible quantitative results;

▶One-stop support for experimental design and bioinformatics analysis, providing reliable functional validation conclusions in combination with gene expression patterns;

▶Direct visualization of gene expression locations, intuitively reflecting the temporal and spatial expression characteristics of the target gene without relying on indirect markers;

▶Capable of performing qualitative staining and quantitative detection on multiple batches of samples simultaneously, supporting both high-throughput screening and detailed validation;

▶Multiple quality control measures including staining gradient optimization, negative control settings, and repeated experimental verification, significantly reducing false-positive results;

▶Ability to assess GUS protein expression levels through enzymatic activity quantification, further correlating the expression abundance of the target gene with its functional activity.

Service Process

Article Case

The GUS reporter-aided analysis of the promoter activities of Arabidopsis ACC synthase genes AtACS4, AtACS5, and

AtACS7 induced by hormones and stresses

academic journal：Journal of Experimental Botany

GUS expression of AtACS4TGUS (A), AtACS5TGUS (B), and AtACS7TGUS (C) recombinant transgenes in the developing transgenic plants. (a) 3-d-old etiolated seedling, (b) 1-week-old light-grown seedling, (c) 2-week-old light-grown plant, (d) 4-week-old light-grown plant, (e) rosette leaves of an adult plant with a 1 cm long inflorescence located at the centre of the rosette as indicated by an arrow. The numbers in panels (d) and (e) indicate the order of leaf appearance. The GUS staining method is described in the Materials and methods..

Applicable Fields

▶Analyze the spatial and temporal expression and expression strength of gene promoters.

▶Perform qualitative analysis of promoter activity through histochemical staining, and quantitative detection of promoter activity can also be conducted.

▶Identify the cis-acting elements of promoters.