The Jackman Lab, from left to right: Bill Jackman (PI), Andrea Jowdry (technician), and Bowdoin College undergraduate researchers Hana Littleford, Sarah Liu, Jeff Yu and Zac Fox.
Professor William Jackman’s Developmental Biology Group at Bowdoin College in Brunswick, Maine, is investigating the genetic control of vertebrate embryonic tooth development (odontogenesis). In particular, they are interested in how cell-cell signaling controls cellular behaviours such as proliferation, migration, and apoptosis, during tooth organogenesis. A variety of fish species are used as models in this research, including zebrafish.
One of the group’s most exciting projects involves the use of zebrafish reporter transgenics to study embryonic tooth development. Fluorescence in situ hybridization (FISH) and antibody-labeling in zebrafish embryos are routinely performed, and confocal microscopy is used to visualize fluorescently labeled cells in fixed or live tooth germs.
In order to effectively increase the fluorescent signal in their experiments, the team uses Tyramide Signal Amplification (TSA™) Technology. The result is vastly improved sensitivity, without loss of resolution or increase in background.
The group finds that the difference between a normal signal and a TSA signal often makes a huge difference in their work. Professor Jackman says, “What we particularly like about TSA is how even on a bad day the signal looks really good. We often have new students learning how to do embryo antibody-labeling and with all of the steps that can go wrong, it is great to have the most signal possible each and every time”.
The confocal images below show developing zebrafish tooth germs at three successive stages of development in a transgenic reporter line, dlx2b:GFP. The dlx2b gene encodes a transcription factor which is essential for the correct formation of teeth and is one of the first genes expressed in the tooth region during development. The GFP signal is amplified with an anti-GFP antibody and TSA. The cell nuclei are stained with SYTOX® Orange. At early stages of development, only the inner dental epithelium is labeled (arrows), but at later stages of development, expression also turns on in the dental papilla (arrowheads).
Development of zebrafish tooth germs. The GFP signal has been amplified using TSA (see text for details).
A better understanding of how cells are controlled during odontogenesis could contribute to innovative future regenerative dental therapies. Discovering how organogenesis has changed between fish species will also teach us about the interface between development and evolution.
Find out more about Tyramide Signal Amplification (TSA™) Technology.
Find out more about the Jackman Developmental Biology Group.
William Jackman is an Assistant Professor of Biology at Bowdoin College and is fascinated by the evolution of the genetic mechanisms of developmental patterning, especially in regard to the development and evolution of teeth. William gained his Ph.D. from the University of Oregon in 2000 and then went on to perform post-doctoral research at the University of Colorado before joining Bowdoin College in 2007.