DEVELOPMENTAL EXPRESSION OF LAMININ-5 AND HD1 IN THE INTESTINE - EPITHELIAL TO MESENCHYMAL SHIFT FOR THE LAMININ GAMMA-2 CHAIN SUBUNIT DEPOSITION

We report the expression pattern of hemidesmosome-associated proteins laminin-5, composed of alpha 3 beta 3 gamma 2 chains, and HD1 in the d eveloping mouse and human intestine, an organ in which variations in s tructure and function parallel morphogenesis and differentiation. Immu nocytochemistry analysis revealed the coexpression of laminin-5 and HD 1 at the basal pole of differentiating epithelial cells. Distinct noti ceable variations occurring in the location of laminin alpha 3 chain i n development of mouse gut were stressed by the reverse transcriptase- polymerase chain reaction data. A peculiar finding was also the locati on of laminin gamma 2 chain in the intestinal muscle coat. The cellula r origin of laminin gamma 2 chain was examined by immunocytochemistry on interspecies hybrid intestines with specific antibodies recognizing mouse antigens. Complementary and sequential production of laminin ga mma 2 chain was observed, by epithelial cells as establishment of the basement membrane occurs and by mesenchymal cells in the more differen tiated organ. These results support the concept of mesenchymal involve ment in deposition of basement membrane molecules, a crucial process f or intestinal differentiation. Taken together these data provide the f irst evidence for the coexpression of hemidesmosome-associated protein s in the gut, a non-stratified tissue. (C) 1996 Wiley-Liss, Inc.