Immunohistochemical Distribution of Laminin-5 γ 2 Chain and its Developmental Change in Human Embryonic and Foetal Tissues

Lu W., Miyazaki K., Mizushima H., Nemoto N.

The Histochemical Journal, 2001

Here, immunohistochemical distribution of laminin γ2 chain, a subunit of the basement membrane protein laminin 332, was examined in 19 cases of human embryos and foetuses ranging from 4 to 25 weeks of gestation. Laminin γ2 was first detected in the basement membranes underlying ectodermal epithelial tissues, such as the skin and tooth, as early as 5–6 weeks of gestation. Between 6–7 and 12–13 weeks, laminin γ2 was detected in the basement membranes of various endodermal epithelial tissues, such as the bronchus, oesophagus, stomach, intestines, urinary bladder, gallbladder, and hepatopancreatic duct. The deposition of laminin γ2 in the basement membrane was associated with the process of morphogenesis. In the small intestine, laminin γ2 first appeared in the basement membrane of the primitive short villi, and its level gradually increased in the villus region but decreased in the cryptic region during the maturation of the organ. In addition, non-basement membrane immunoreactivity for laminin γ2 was detected in some mesoderm-derived tissues, such as the cartilage and skeletal and smooth muscle fibers. These results suggest a common role of laminin 332 and some specific roles of its γ2 chain in the morphogenesis of human tissues.