Differential display

Abstract

Differential display (DD), as first described by Liang and Pardee 1,2 in 1992, is a reversetranscription polymerase chain reaction (RT-PCR)-based method for rapid identification of differentially expressed genes. It offers several advantages over conventional methods, 3 such as differential screening of complementary deoxyribonucleic acid (cDNA) libraries and subtractive cDNA library preparation and screening (see Chapter 9). First, employing PCR reduces the amounts of starting ribonucleic acid (RNA) needed. At the same time, it enables amplification of transcripts, thus permitting detection of lower-abundance messenger RNA (mRNA) species that are frequently undetectable using hybridization-based methods (e.g., conventional subtractive library screening). Second, the entire DD procedure from RNA extraction to banding-pattern detection can be completed in a few days, whereas hybridization signals from library construction and screening-based approaches routinely take weeks to obtain. Third, DD is not limited to pairwise comparisons, but it can be readily expanded to compare transcript profiles among multiple, closely related samples, thus allowing time-course studies or developmental gradients to be followed. Although it does not offer the high throughput of DNA microarrays (see Chapter 15), it is versatile and relatively inexpensive to set up and perform in most molecular biology labs.