| OBSERVATION'S |
In the second branch of proteomics, functional proteomics, "our goal is to express and examine --"to produce proteins and look at what they do. What are their functions?" Author believes it's crucial that every gene be "captured" so researchers can easily produce the corresponding proteins, generate reagents specific to those proteins, and analyze their functions in a high-throughput manner. Scientists can already perform such studies by using complementary DNA (cDNA) libraries to generate the proteins, he notes. But a cDNA library is essentially a snapshot of all the RNA in a cell and will have many more copies of common housekeeping genes than rare regulatory genes. Therefore, researchers must sift through a multitude of less interesting genes to examine the rare ones--like looking for a needle in a haystack.
Moreover, cDNA libraries are made from cells, and only about 30% of the coding potential of a cell is expressed at any one time. This means that a researcher carrying out a cDNA-based analysis is going to be missing about 70% of a cell's genes right off the top. It would instead be preferable to express and examine proteins by carrying out one assay per gene, author says or about 30,000 assays for all the proteins encoded directly in the human genome. He says his group "calculated that a grocery clerk looks at 30,000 items in two weeks--and if you think about it, that's a complex assay. That's taking an object, using an instrument to measure a value from that object, and physically removing it from one location to another. So we figure if a grocery clerk can do that, a postdoc or graduate student could do 30,000 assays in six months or a year."The goal, he says, "is to be able to study proteins in the same way that the pharmaceutical industry can currently study small molecules: hundreds or thousands at a time in a very high-throughput setting. So how do we get there?"
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