“Native” striated collagen produced by chick notochordal epithelial cells in vitro

We report here the observation of striated collagen produced by notochordal cells in vitro. Fibrils with collagen‐like striations were seen in large intercellular spaces following three days of incubation in vitro. Surprisingly, similar fibrils and large sheets (1,500 Å wide) of collagen showing a 510 Å periodicity were seen in notochordal tissues cultured in the presence of β‐aminopropionitrile (BAPN), a known inhibitor of cross‐linking in tropocollagen. These observations support the view that the notochord should be considered one of several embryonic epithelial tissues known to secrete collagen.