The ultrastructure of polygonal networks in chick embryonic cells in vitro

Polygonal networks in cultured chick endoderm cells are ordered arrays of actin microfilaments situated just beneath the dorsal cell surface. Each strut is formed from a bundle of microfilaments and 5-7 bundles intersect at each node. Dense bodies are seen in nodes and some struts. At its periphery the network is attached to the substrate at the termini of long radial struts. Most of the network is resistant to detergent extraction. Sliding microfilaments can explain the observed behaviour of networks in live cells.