The Degradation of the Basement Membrane in the Metamorphic Organs during the Larval-Pupal Transformation of Bombyx mori

抄録

The basement membrane is a thin, specialized extracellular matrix surrounding most tissues in all insects, and the disintegration of the basement membrane facilitates cell movements, such as the rearrangement of cells during development. Histological analysis of the basement membrane in the wing discs, midgut, fat bodies, and silk glands of Bombyx mori provided insights into their assembly during metamorphosis. Our observations revealed that the basement membrane was not degraded in the wing discs, fat bodies, or midgut during the larval feeding stages, but was partially or completely degraded during the later spinning and early pupal stages. In contrast, the basement membrane of the silk glands was not degraded at any developmental stage, and its thickness increased during the late spinning and early pupal stages. The degradation of the basement membrane during the late spinning stages in the above tissues correlated with the expression pattern of BmADAMTS-like (Bombyx mori a disintegrin and metalloproteinase with thrombospondin-type I motif) gene expression.