Xenopus laevis is an ideal model system for investigating the mechanisms of pattern formation. The ability to express exogenous mRNA or introduce morpholinos into cleavage-stage Xenopus embryos has allowed gain- and loss-of-function experiments that reveal molecular-genetic control of development and regeneration. However, injection of mRNAs into cleavage-stage embryos provides limited spatio-temporal control: It is difficult to limit targeting to small regions (e.g., inducing foci of expression) and the fate map does not facilitate targeting some tissues, such as those of the tail. Likewise, early injection can result in unwanted developmental defects because mRNA can be translated long before the desired time point. These are especially important limitations when studying developmental and regenerative processes during the gastrula to tailbud stages. Although transgenic techniques allow precise control over spatio-temporal expression of genes when the appropriate promoter is available, the process of creating stable transgenic animals is time-consuming. Electroporation provides an alternative method for delivering mRNA and other nucleic acids, enabling the targeting of single cells or groups of cells at any stage of development. This protocol describes detailed electroporation parameters for the transfection of mRNA into a wide range of tissues in embryos at gastrula to tailbud stages, with high efficiency and expression as early as 4 h post electroporation.
MicroRNAs (miRNAs) are a large family of endogenous noncoding RNAs that, together with the Argonaute family of proteins (AGOs), silence the expression of complementary mRNA targets posttranscriptionally. Perfectly complementary targets are cleaved within the base-paired region by catalytic ... more
Intrinsic optical changes (light scattering signals) occur in mammalian nerve terminals during and immediately following the arrival of the action potential. In the neurohypophysis (posterior pituitary gland), the action potential is coupled to calcium-mediated secretion of the neuropeptid ... more
The skeleton as an organ is widely distributed throughout the entire vertebrate body. Wnt signaling has emerged to play major roles in almost all aspects of skeletal development and homeostasis. Because abnormal Wnt signaling causes various human skeletal diseases, Wnt signaling has become ... more