Immunocytochemical study of fibronectin in the sea lamprey, Petromyzon marinus, and the Atlantic hagfish, Myxine glutinosa.

Immunoreactive fibronectin-like material was localized within tissues of agnathans (hagfishes and lampreys) by an immunoperoxidase technique. Fibronectin was detected in basement membranes and in loose and dense connective tissues throughout the agnathan body. A fibronectin-like component was also identified in the plasma of both lampreys and hagfishes. The results indicate that fibronectin or a fibronectin-like material is a major component of agnathan connective tissues. Although there were some variations in the localization of fibronectin both between the lamprey and the hagfish and between agnathan and other vertebrate tissues, the generalized pattern of distribution of fibronectin in the agnathans supports the view that this protein, like that in higher vertebrates, plays a role in cell-matrix adhesion and tissue organization.