Basement Membrane (Type IV) Collagein Is Found in Hydra

Abstract

Hydra, like all Cnidarians, has two cell layers in its body wall. The outermost layer (external) is called the epidermis and the innermost layer (internal) is called the gastrodermis. Between these two layers lies the mesoglea, which is non-cellular in some animals and cellular in others. Three functions of the mesoglea have been proposed: the first is for support (skeleton-like), the second is that it acts as a insertion-antagnoist and aids in muscle movement, and the third is that it plays a major role in cell movement. Due to its functions and position in the body of the hydra, this mesoglea is an early form of collagen. Genomic hydra DNA was subcloned into Blue Scribe plus vector phage and infected into bacteria. A radioactive mouse type IV collagen cDNA probe was used to screen the hydra DNA for a sequence complementary to the mouse type IV sequence. The DNA of the colonies that hybridized with the mouse cDNA probe were sequenced by the Sanger Dideoxy sequencing method. The results showed a Gly-x-y repeat, thus indicating that the hydra DNA does in fact contain basement membrane (type IV) collagen.