Xenopus

Xenopus is a taxonomic genus of African clawed frogs used in experimental biology. Xenopus laevis is an important example. Its large egg cells and oocytes make manipulations of individual cells possible, allowing researchers to change a defined component and observe development or membrane function.

In John Gurdon's 1962 somatic cell nuclear transfer experiments, nuclei from intestinal epithelium of feeding tadpoles were introduced into eggs whose own nuclear contribution had been removed. A nuclear marker helped identify the donor origin, while embryonic-nucleus controls tested whether the recipient eggs and procedure could support development. Successful development showed that differentiation did not necessarily eliminate the nuclear information needed for other cell types.^[ref]

A different use treats the oocyte as a test cell for a cloned membrane protein. The 1993 aquaporin-2 study introduced the channel's RNA into Xenopus oocytes and measured the resulting increase in water permeability. Comparing injected and control cells turns swelling in a defined external solution into evidence that a candidate protein can provide a pathway for water across a cell membrane.^[ref]