LAMININ EXTRACTION AND DISORGANIZATION OF COLLAGEN FIBRILS IN SNAIL MUSCLES BY EDTA TREATMENT

Snail muscles were extracted by a solution of EDTA and electron micros copy showed that the extract contained dispersed, depolymerized collag en fibrils and cross-shaped laminin-like structures. The extracts were purified by ultracentrifugation followed by two different procedures which enriched the content of laminin-like structures. The laminin-rel ated molecules displayed unique properties when analyzed by biochemica l, immunological and morphological methods. Electrophoretic patterns o f the molecular form purified primarily by ion exchange chromatography , resembled EHS-tumor laminin and displayed a cruciform shape when vie wed by electron microscopy. Immunohistology, using antiserum obtained against the agarose gel-purified protein, showed that this laminin was primarily located in the extracellular matrix surrounding muscle fibe rs. Western blots using anti-EHS laminin antibody showed reaction of a 300 kDa subunit of this snail laminin. The protein obtained by anothe r procedure, initially using gel filtration, followed by ion exchange chromatography, also appeared to be a laminin. It had a collapsed cruc iform appearance when viewed by electron microscopy. It contained seve ral different subunits, one of which, ca 300 kDa, reacted with anti-EH S-laminin antibody and with anti-snail laminin antibody. In contrast, EHS laminin did not react with the anti-snail laminin antibody. The co mposite results suggest that at least two different forms of laminin a re extractable from snail muscle and that they share molecular propert ies and immune determinants with mouse tumor laminin.