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Novel Ion Channels Can Be Characterized by a Combination of Oocyte Expression and Patch Clamping

المؤلف:  Harvey Lodish, Arnold Berk, Chris A. Kaiser, Monty Krieger, Anthony Bretscher, Hidde Ploegh, Angelika Amon, and Kelsey C. Martin.

المصدر:  Molecular Cell Biology

الجزء والصفحة:  8th E , P501

2026-06-18

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 Cloning of human-disease-causing genes and sequencing of the human genome have identified many genes encoding putative channel proteins, including 67 putative K⁺ channels. One way of characterizing the function of these proteins is to transcribe a cloned cDNA in a cell-free system to produce the corresponding mRNA. Injecting this mRNA into frog oocytes and taking patch-clamp measurements of the newly synthesized channel protein can often reveal its function (Figure 1). This experimental approach is especially useful because frog oocytes normally do not express any channel proteins on their plasma mem branes, so only the channel under study is present in the membrane. In addition, because of the large size of frog oocytes, patch-clamping studies are technically easier to perform on them than on smaller cells.

Fig1. The oocyte expression assay is useful in comparing the function of normal and mutant forms of a channel protein. An oocyte from the follicle of a frog is first treated with collagenase to remove the surrounding follicle cells, leaving a denuded oocyte, which is then microinjected with mRNA encoding the channel protein under study. See T. P. Smith, 1988, Trends Neurosci. 11:250.

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