A team at UC San Diego has developed a technique in Drosophila fruit fly cells that can watch the level of gene expression for several genes at once in living cells.
“Multiplex labeling has allowed us to directly map the activation patterns of micro-RNA genes, which were hitherto undetectable,” says William McGinnis, a professor of biology at UCSD and co-principal investigator of the study. “Micro-RNAs were known to be important in development, but this is the first evidence indicating that these genes can control the embryonic body plan.”
Different colored fluorescent molecules can be used to identify transcripts from different genes in the same cell. It works even if one gene is much more active than another, because the amount of fluorescence of each color is quantified separately.
“When using the microscope to measure the fluorescence, the light is fanned out into a rainbow, and each color is read through a separate channel,” explains Bier. “That way if the light is 90 percent blue and ten percent yellow, it might look blue to the naked eye, but the microscope detects each color present.”
According to Bier, multiplex labeling fills a gap in developmental biologists’ toolkit between gene chips, which can identify several hundred gene transcripts at a time, but not their location, and methods that can reveal the identity and location of up to three gene transcripts simultaneously—though not if they are in the same cell. So far the researchers have used multiplex labeling to visualize the activity of up to seven genes at the same time, but they predict it will be possible to increase this to 50.
Newly developed, ultra-bright fluorescent molecules make the multiplex labeling technique possible. The fluorescent molecules were provided by Molecular Probes, Inc., and the company’s scientists also shared their expertise with the UCSD researchers. Developing an effective way to attach the fluorescent molecule to the RNAs complementary to the gene transcripts, and perfecting the overall labeling process were also pivotal in the development of the technique.
These researchers say additional work has to be done to adjust their technique to work in other species. They foresee its eventual use in the study of cancer tumor development and in other diseases and normal biological processes.
This research is yet example of how biologists are developing techniques that are speeding up the rate at which biological systems can be studied and understood.
|Share |||Randall Parker, 2004 August 09 01:48 AM Biotech Advance Rates|