Gene Overexpression Services

Gene overexpression vectors are key tools for studying gene gain-of-function, generating stable expression cell lines, and producing recombinant proteins. Alfa Cytology is dedicated to the construction and optimization of overexpression vectors, offering a diverse range of vector backbones and expression systems to meet varying needs from transient expression to stable integration. Our senior scientists will design and construct efficient, reliable overexpression vectors based on your target gene, host cell type, and downstream applications, supporting every step from gene function studies to protein production and drug screening.

Introduction to Gene Overexpression

Gene overexpression is one of the most classic and direct approaches for studying gene function. Its core principle involves cloning the full-length coding sequence (CDS) of the gene of interest into an expression vector containing a strong promoter (e.g., CMV, EF1α), followed by introduction into host cells via transfection or transduction, thereby achieving stable or transient expression of the target gene at levels exceeding endogenous expression. By comparing phenotypic differences between overexpression and control groups in proliferation, migration, apoptosis, drug resistance, and signaling pathway activation, researchers can systematically evaluate the gene's functional role in specific biological processes. In cancer research, gene overexpression has exceptionally broad applications. It serves not only as a standard approach for oncogene functional validation but also as an important tool for dissecting signaling pathway regulatory relationships. By overexpressing key pathway node molecules combined with downstream effector detection, upstream and downstream regulatory logic can be effectively elucidated. Furthermore, overexpression systems are commonly used for recombinant protein production, protein subcellular localization studies, protein-protein interaction research, and druggability assessment of drug targets. Depending on experimental objectives, gene overexpression can be achieved through transient or stable expression. Transient expression enables high-level target gene expression within 24–72 hours post-transfection, suitable for rapid functional validation and protein production; stable expression, achieved through lentivirus-mediated gene integration or drug selection, establishes cell lines with long-term stable overexpression, suitable for long-window functional studies and in vivo transplantation experiments.

Fig. 1 Diagram of eukaryotic overexpression vector construction. (Ballav S, et al.; 2024)

Our Services

Alfa Cytology's Gene Overexpression Services encompass multiple expression systems, including non-viral eukaryotic expression vectors and viral backbone vectors such as lentivirus and AAV, which can be flexibly adapted to transient and stable transfection needs based on experimental timeline, expression duration, and delivery efficiency.

We offer a variety of promoters (e.g., CMV, EF1α, CAG), fusion tags (e.g., Flag, HA, GFP, His), and selection markers (e.g., Puromycin, Blasticidin, Neomycin, Hygromycin), supporting diverse applications from gene function validation, protein localization and interaction studies to stable cell line construction and animal model development, accommodating a wide range of experimental designs. Importantly, all vectors we provide undergo full-length sequencing verification to ensure 100% sequence accuracy.

Vector Design and Construction

Based on your research objectives, we design and construct expression vectors carrying the gene of interest. Services include:

• PCR amplification of the target gene and ORF cloning.
• Codon optimization (if required).
• Multiple promoter options: CMV, EF1α, LTR, tissue-specific promoters, and Tet-On/Off inducible systems.
• Multiple fusion tag options: Flag, HA, Myc, GFP, mCherry, Luciferase, His-tag, GST, etc.
• Selection markers: Puromycin, Blasticidin, Neomycin, Hygromycin, etc.
• Full-length sequencing verification to ensure 100% accuracy of the inserted sequence.

Expression Validation

All constructs undergo rigorous expression validation:

• Plasmid sequencing verification and restriction enzyme digestion analysis.
• Expression detection after transfection into standard cell lines (qPCR, Western blot).
• Subcellular localization detection (fluorescence microscopy), if required.

Available Vector Types

We also offer construction services for overexpression stable cell lines, including transfection/transduction, monoclonal screening, stable cell line establishment, and overexpression validation (qPCR, Western blot).

Specifications

Applications of Gene Overexpression Services

Target Discovery

• Oncogene screening and identification: Overexpress candidate genes in tumor cells to screen for genes with oncogenic functions and discover novel driver genes.
• Gain-of-function screening: Perform genome-wide gain-of-function screening using overexpression cDNA libraries to identify key genes that promote cell proliferation and survival.
• Druggability assessment of drug targets: Overexpress specific candidate targets to evaluate their potential for pharmacological intervention.

Target Validation

• Functional validation of oncogenes: Overexpress candidate oncogenes in multiple tumor cell lines to systematically assess their effects on phenotypes such as proliferation, migration, invasion, and evasion of apoptosis.
• Validation of drug resistance-related genes: Overexpress candidate drug resistance genes to verify their functional roles in drug tolerance.
• Synthetic lethality studies: Overexpress relevant genes in specific genetic mutation backgrounds to explore synthetic lethal targets, providing a basis for precision therapeutic strategies.

Preclinical Evaluation

• Establishment of in vivo overexpression models: Lentiviral or AAV-mediated overexpression vectors are used for in vivo gene delivery to establish CDX models for evaluating the tumor-promoting effects of genes in vivo.
• Recombinant protein production: For antibody production, enzyme activity studies, and structural biology research.
• IND-enabling studies: Provide key efficacy data from overexpression cell lines and in vivo models to support IND filing.

Workflow of Gene Overexpression Services

Project Consultation and Strategy Design

Our scientific team communicates closely with you to understand your research objectives, gene information, cell type, and downstream application requirements, and designs the optimal overexpression vector construction strategy.

Vector Design and Construction

Based on the approved plan, PCR amplification of the target gene, ORF cloning, codon optimization, and vector construction are performed, followed by full-length Sanger sequencing verification.

Expression Validation

The constructed expression vector is transfected into a standard cell line, and the expression of the target gene at the mRNA and protein levels is assessed by qPCR and Western blot to ensure reliable vector functionality.

Delivery and Downstream Application Support

Overexpression plasmids, glycerol stocks, and complete validation reports are delivered. If stable cell line construction or viral packaging is required, seamless integration with the corresponding service platforms can be provided.

From validating a candidate oncogene to producing recombinant protein or building a stable overexpression model, Alfa Cytology designs and delivers overexpression constructs tailored to your gene, host cell, and downstream goals. Contact us with your expression requirements, and we will help you move from construct to conclusion faster.

For research use only.