June 21, 2013

Good things come in small packages.  Maybe I’m referring to the burst of antioxidants jammed into tiny blueberries.  Maybe I’m referring to my tiny three year-old who yells, “Come oooon, THAT was funny!” when I don’t laugh loudly enough at her jokes.  Or maybe I’m referring to C. elegans.  These worms are tiny, but pack a serious punch of significant biology that helps us learn about important cellular processes.  Today’s image is from a paper that serves as an excellent example of this.

During cell invasion, a cell is able to breach and cross over the basement membrane that underlies a sheet of epithelial cells.  Cell invasion occurs throughout development and in the spread of cancer, yet biologists studying cell invasion have been challenged by the difficulty of visualizing the event.  A recent paper describes the development of live-cell imaging methods for studying cell invasion, using the worm’s anchor cell.  The anchor cell in the developing worm’s uterus breaches the basement membrane in order to link uterine and vulval tissues, and its transmigration is precisely timed.  Hagedorn and colleagues followed the interactions between the invading anchor cell and the basement membrane, and found very dynamic actin-based invadopodia that first breach the basement membrane.  These protrusions then stabilize to expand the breach and cross into the vulval tissue.  Anchor cell invasion depends on the netrin receptor UNC-40 (DCC) at the interface between the anchor cell and basement membrane.  In the time-lapse images above, the invading protrusion (cyan in top, grayscale in bottom) can be seen breaching the basement membrane (purple) and invading the vulval tissue underneath.

Hagedorn, E., Ziel, J., Morrissey, M., Linden, L., Wang, Z., Chi, Q., Johnson, S., & Sherwood, D. (2013). The netrin receptor DCC focuses invadopodia-driven basement membrane transmigration in vivo originally published in the Journal of Cell Biology, 201 (6), 903-913 DOI: 10.1083/jcb.201301091