Mago's Role in Embryological Development

Development of the embryo is controlled by complex signaling pathways that include molecules acting both inside and outside of the cell. In vertebrates, many of the factors that control formation of the posterior nervous system (the hindbrain and spinal cord) are unknown.

Originally identified in Drosophila, the mago protein is highly conserved between fly, mouse, frog, and human embryos. We identified a protein, mago nashi, as a molecule that can induce spinal cord tissue in embryos of the frog Xenopus laevis. Our current goal is to determine mago's role in the development of the nervous system.

To reveal mago's place within the genetic cascade (controlling spinal cord formation), we use Xenopus laevis embryos. By injecting undifferentiated cells with known inducing molecules, and analyzing how mago's expression is affected, we can identify the signals that act upstream of mago in the genetic pathway. Based on the same line of logic, it would also be reasonable to inject early embryos with mago, and check for the induction of other genes. This is a method for identifying genes normally expressed subsequent to mago. By understanding what induces mago, and what genes are induced by mago, we hope to formulate a clearer picture of mago's role in early neural development.

The strategies for revealing mago's function are supported by several routine techniques. We obtain eggs from adult female frogs and fertilize them to begin the process. These "ferts" are used for embryo injections and removal of a small piece of undifferentiated ectodermal tissue (cap) from the embryo. This manipulation is used to obtain undifferentiated ectoderm cells that have been flooded (by injection) with certain neural inducers.

These ectoderm "caps" are pulverized to obtain their mRNA. The mRNA is extracted and reverse transcribed, yielding cDNA. This cDNA is then subjected to PCR using primers with the sequence of specific genes. By using simple gel electrophoresis, we then analyze gene activation. We can identify genes that are turned on (or transcribed) in response to the injected inducing molecules. We hope, by this methodology, to uncover the role of mago nashi in early spinal cord development.