

Gene Expression - Applications

Ectopic gene expression for gene analysis and protein science

Over-expressing genes can offer insight into gene function at multiple levels. Gain-of-function experiments often result in phenotypic changes that provide the counterpart to loss-of-function studies, such as gene knockdown.

Gene expression occurs continuously and simultaneously in cells in order to produce proteins and non-protein coding RNAs, such as rRNA, and tRNA, siRNA. Proteins and RNAs are the functional units of gene expression that catalyze all cellular reactions. Gene expression constructs, such as cDNAs and ORFs, can be used for over-expression studies, enabling a protein of interest to be analyzed for effect on cellular phenotype, intracellular localization, or for the isolation and purification of a protein for further study.

Gene Expression Tools

Complementary DNA (cDNA) and open reading frames (ORF) are two tools derived from native mRNA that can facilitate gene expression and over-expression assays.

  • cDNA is derived from mRNA and contain the ORF as well as all or part of the 5' and 3' untranslated regions.
  • ORFs are created from cDNA by removing the untranslated regions leaving just the protein coding open reading frame.

Pre-cloned cDNAs and ORFs reduce the amount of time needed to clone or synthesize a gene of interest, allowing researchers to spend more time analyzing the results of their over-expression experiment, and less time creating the expression construct itself.

Gene expression as a tool for gene analysis and protein science

gene expression pathway lg

Schematic of gene product translation and expression in a eukaryotic cell. Once in the nucleus, the cellular machinery recognizes the promoter, transcribes the protein coding sequence into mRNA and translates the protein. The resulting gene product can cause alterations in phenotype, be purified for further processing or to be tracked via localization to better understand protein function.

Featured Products

Gene Expression (cDNAs and ORFs)


Mammalian cDNAs

  • Derived from mRNA and including 5’ and 3’ UTRs, our cDNA collections are ideal for overexpressing a gene in the context of native regulation.

Mammalian ORFs

  • With both 5’ and 3’ UTRs removed, open reading frames (ORFs) provide a shortcut to protein expression.

Non-Mammalian cDNAs and ORFs


Featured Resources

cDNA Clones and Plates - Technical Manual

  • cDNA Clones and Plates - Technical Manual

Top five considerations for ORF selection

  • This list presents the major considerations to help you quickly and effortlessly select the right clone(s) for your over-expression project.