DNA microarray technology to identify genes controlling spermatogenesis

Though most cells in our bodies contain the same genes, not all of the genes are used in each cell. Some genes are turned on, or "expressed" when needed. Many genes are used to specify features unique to each type of cell. Liver cells, for example, express genes for enzymes that detoxify poisons, while pancreas cells express genes for making insulin. To know how cells achieve such specialization, scientists need a way to identify which genes each type of cell expresses.

Microarray technology now allows us to look at many genes at once and determine which are expressed in a particular cell type. DNA molecules representing many genes are placed in discrete spots on a microscope slide. This is called a microarray. Thousands of individual genes can be spotted on a single square inch slide! Next, messenger RNA--the working copies of genes within cells (and thus an indicator of which genes are being used in these cells)--is purified from cells of a particular type. The RNA molecules are then "labeled" by attaching a fluorescent dye that allows us to see them under a microscope, and added to the DNA dots on the microarray. Due to a phenomenon termed base-pairing, RNA will stick to the gene it came from. After washing away all of the unstuck RNA, we can look at the microarray under a microscope and see which RNA remains stuck to the DNA spots. Since we know which gene each spot represents, and the RNA only sticks to the gene that encoded it, we can determine which genes are turned on in the cells! Some researchers are using this powerful technology to learn which genes are turned on or off in diseased versus healthy human tissues. The genes that are expressed differently in the two tissues may be involved in causing the disease.

Our lab, in collaboration with Dr. Stuart Kim's lab at Stanford, wanted to know which genes are specifically involved in making worm sperm. To find out, we purified RNA from worm populations that make either oocytes only (worms mutated in a gene called fem-1, which can't make sperm), or sperm only (fem-3 mutants, which make no oocytes). We then labeled the two RNA preparations with different colored dyes, and added them to a microarray that contained several hundred worm genes. By determining which genes were expressed only in the worms that make sperm, we identified some of the genes that allow these cells to develop, move towards the unfertilized egg, and fuse with it. We recently examined microarrays that contain all of the approximately 19,000 worm genes. By identifying all of the genes involved specifically in sperm development, we hope to understand our half of the tale of how a new worm is created!

NEW! A global profile of germ line gene expression in C. elegans
read our paper, view our results

Search for References on Microarray Research in Worms

Other DNA Microarray Web Sites

MGuide Microarray protocols fromPatrick Brown lab, Stanford University

National Human Genome Research Institute Microarray Project

Stuart Kim Lab Microarray Page
Andreas Matern's Microarray Links
Gene Chips (DNA Microarrays) Home Page

DNA Microarray Links Page at the Ecole Normale Superieure, Paris

Lab-on-a-Chip.com resources and news on microarray research

Arrayit.com electronic library of microarray publications