epi-1 accumulates between the primary tissue layers near the completion of gastrulation (~250 minutes).
epi-1 antiserum stains all the major basement membranes during the remainder of embryogenesis and throughout larval development and in the adult. Although
epi-1 staining is weak in the basement membranes surrounding pharynx, intestine, body wall muscle and epidermis, the staining is strong in the basement membranes surrounding gonad, distal tip cell, vulval muscle, intestinal muscle, anal depressor muscle and coelomocytes. These basement membranes are notable in that they are thick and appear to have mainly the alphaB-containing laminin isoform.