Microinjection of Xenopus tropicalis Embryos

Microinjection is an important technique used to study development in the oocyte and early embryo. In Xenopus, substances such as DNA, mRNA, and morpholino oligonucleotides have traditionally been injected into Xenopus laevis, because of their large embryo size and the relatively long time from their fertilization to first division. In the past few decades, Xenopus tropicalis has become an important model in developmental biology; it is particularly useful in genetic studies. The advent and rapid development of CRISPR-Cas9 technology has provided an array of targeted gene manipulations for which X. tropicalis is particularly suited. The equipment and protocol for X. tropicalis microinjection is broadly transferable from X. laevis There are important differences between the species to consider, however, including the smaller embryo size and faster embryo development time in X. tropicalis There are a number of solutions and reagents that differ in concentration and composition as well. Here we describe a microinjection protocol specifically for studies in X. tropicalis.