To study the biological function of wound healing, the researchers needed to develop a "clean puncture wounding" protocol to damage the epidermis of fly embryos without allowing bacteria to infect the breach, which would complicate the study. Researchers study fly embryos rather than adult flies because it's easier and the embryos offer a wider range of genetic mutations than adult flies. The first step was to collect fly eggs, which contain developing embryos, and bleach them to remove the shells. Next they impaled the embryos with microneedles, like using a toothpick to spear an olive.
Key to the technique was injecting trypsin, a member of a family of enzymes called serine proteases, which control cell-to-cell signaling. Trypsin activates genes involved in wound healing throughout the embryo, and it also amplifies the response in the affected cells, revealing new players in the choreography of healing. "We took advantage of trypsin as a powerful wounding tool to pinpoint which genes are 'turned on' versus which genes are 'turned off' after wounding," Ms. Patterson said.
Researchers then looked at which genes were turned on and off at 30, 60, and 120 minutes post-stabbing that illuminate events as the borders of a small, clean wound close. The researchers were surprised to discover that an immune response begins as soon as the cuticle has been breached, with signals that prepare the embryo sho
|Contact: Phyllis Edelman|
Genetics Society of America