Differential display

Differential Display

Differential Display

Differential display is a molecular biology technique used to compare gene expression patterns between different samples. It is commonly used to identify genes that are differentially expressed under specific conditions or in different tissues. This technique allows researchers to gain insights into the molecular mechanisms underlying various biological processes.

History

Differential display was first introduced by Liang and Pardee in 1992 as a method to identify differentially expressed genes. It was initially developed to study cancer-related genes but has since been applied to various fields of research, including developmental biology, immunology, and neurobiology.

Methodology

The differential display technique involves several steps:

1. RNA extraction: Total RNA is isolated from the samples of interest using standard methods.

2. Reverse transcription: The isolated RNA is reverse transcribed into complementary DNA (cDNA) using reverse transcriptase enzyme and random primers.

3. PCR amplification: The cDNA samples are amplified using PCR with a set of gene-specific primers and arbitrary primers. The arbitrary primers introduce sequence diversity, allowing the amplification of different subsets of genes.

4. Electrophoresis: The PCR products are separated by gel electrophoresis, typically using denaturing polyacrylamide gels. This separation allows the visualization of differentially expressed genes as distinct bands.

5. Isolation and identification: The differentially expressed bands are excised from the gel, purified, and sequenced. The obtained sequences are then compared to known gene databases to identify the genes of interest.

Applications

Differential display has been widely used in various research areas, including:

1. Cancer research: It has been instrumental in identifying genes associated with tumor development, progression, and metastasis. By comparing gene expression patterns between normal and cancerous tissues, researchers can identify potential therapeutic targets or diagnostic markers.

2. Developmental biology: Differential display has been used to study gene expression changes during embryonic development, organogenesis, and tissue differentiation. It helps in understanding the molecular mechanisms underlying these processes.

3. Immunology: This technique has been employed to investigate gene expression changes in immune cells during immune responses, such as inflammation or infection. It aids in identifying genes involved in immune regulation and response.

4. Neurobiology: Differential display has been utilized to study gene expression changes in the brain under different physiological and pathological conditions. It helps in identifying genes associated with neurological disorders or brain development.

Limitations

While differential display is a powerful technique, it has some limitations:

1. Sensitivity: The technique may not detect genes with low expression levels, as they may not produce visible bands on the gel.

2. Specificity: The arbitrary primers used in the PCR amplification step may introduce nonspecific amplification, leading to false-positive results.

3. Throughput: Differential display is a time-consuming and labor-intensive technique, limiting the number of genes that can be analyzed simultaneously.

Conclusion

Differential display is a valuable tool in molecular biology research for identifying differentially expressed genes. It has contributed significantly to our understanding of gene regulation and the molecular basis of various biological processes. Despite its limitations, it remains a widely used technique in many fields of study.

See Also

• Gene expression
• Polymerase chain reaction
• Gel electrophoresis
• Reverse transcription
• Complementary DNA