Microinjection of DNA Constructs into Xenopus Embryos for Gene Misexpression and cis-Regulatory Module Analysis

Aquatic Freshwater Vertebrate Models of Epilepsy Pathology: Past Discoveries and Future Directions for Therapeutic Discovery

Epilepsy is an international public health concern that greatly affects patients’ health and lifestyle. About 30% of patients do not respond to available therapies, making new research models important for further drug discovery. Aquatic vertebrates present a promising avenue for improved seizure drug screening and discovery. Zebrafish (Danio rerio) and African clawed frogs (Xenopus laevis and tropicalis) are increasing in popularity for seizure research due to their cost-effective housing and rearing, similar genome to humans, ease of genetic manipulation, and simplicity of drug dosing. These organisms have demonstrated utility in a variety of seizure-induction models including chemical and genetic methods. Past studies with these methods have produced promising data and generated questions for further applications of these models to promote discovery of drug-resistant seizure pathology and lead to effective treatments for these patients.

Analysis of Cell Fate Commitment in Xenopus Embryos

The fates of individual cleavage-stage blastomeres and of groups of cells at the blastula through gastrula stages of Xenopus embryos have been mapped in great detail. These studies identified the major contributors of the three germ layers as well as a variety of tissues and organs and several specific cell types. One can use these fate maps to test the commitment of single cells or groups of cells to produce their normal repertoire of descendants, to identify the genes that regulate fate commitment, and to modulate the levels of gene expression in specific lineages to determine gene function in a variety of developmental processes. Here we introduce methods that include how to identify specific blastomeres, inject them with lineage tracers, and alter gene expression levels. We also discuss methods for assaying protein and mRNA expression in situ and for providing novel embryonic environments to test fate commitment. These techniques draw upon classical approaches that are quite easy to perform in the versatile Xenopus embryo.