The Hardin Lab

A C. elegans embryo expressing AJM-1::GFP in which the founder cell Cpaa was ablated to remove the left-hand
dorsal epidermal cells [Ryan King]. Such ablations allow examination of cell autonomy during epithelial cell rearrangement.

Dorsal epidermal cells comprise two rows of epithelial cells that lie along the dorsal midline and extend along much of the anterior-posterior axis. These cells intercalate to form a single row of cells. Since there are only 20 cells that intercalate, it is perhaps the simplest known system for studying directed cell rearrangement during embryonic development. Click on the links to see examples [requires QuickTime]...

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Dorsal intercalation in a wild-type embryo visualized using Nomarski microscopy. Anterior to the left, dorsal view. Frames were acquired at 30 sec intervals. Original movie footage courtesy of E. Williams-Masson (Williams-Masson et al., 1998; PubMed).     Dorsal intercalation in a wild-type embryo visualized using a dlg-1::gfp translational fusion (Koeppen et al., 2001; PubMed). Frames were acquired at 5 min intervals.

We are taking several approaches to study dorsal intercalation that include:

(1) Determining how a Rac/RhoG-dependent actomyosin network regulates intercalation; and
(2) Biomechanical modeling of how dorsal cells rearrange.