*This website was produced as an assignment for an undergraduate course at Davidson College.*
What is an Oligo (dT) Column?
The oligodeoxythymidine (oligo(dT)) affinity column is commonly used as an effective method for the purification of messenger RNA. mRNA proves difficult to isolate because it composes only 1-2% of the total RNA in a cell and because it is heterogenous in size (DeFrancesco, 1998). Oligo (dT) is a very powerful tool because, despite the characteristics of mRNA that make it difficult to purify, it can isolate mRNA by bonding the polyA tail of RNA.
Oligo (dT) was first used to isolate mRNA in 1972 by H. Aviv and P. Leder. Previously, the only messages that were very abundant (beta-globin in reticulocytes, for example) or very unusual (one with an unusual base sequence like that for silk fibroin proteins, for example) had been isolated to any purity at all (DeFrancesco, 1998). Origionally, researchers had to develop Oligo (dT) on their own, but it can now be bought in stock.
Figure 1. This image illustrates one type of Oligo (dT) column. Permission for the use of this image is currently being sought at www.monomer.com.
Oligo(dT) can be utilized in many different ways in order to isolate mRNA. You can bind mRNA to Oligo(dT) on an affinity column, to oligo(dT) cellulose in a slurry, to Oligo(dT) attached to latex beads, to oligo(dT) in spin columns, or to magnetic particles with Oligo(dT) (DeFrancesco, 1998). This list of possible methods illustrates the variety of ways to isolate mRNA; in all methods, Oligo(dT) is obviously the key!
This website focuses on Oligo(dT) used as an affinity matrix in column chromatography, in which Oligo(dT) is attached to beads on the column. The specifics of how this method works are outlined in the next section.
see next section--How Oligo(dT) works
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