SGER: Retroviral Strategies for Conditional Transgenesis in Brain Development

University Of Chicago, Chicago IL

Investigators

Abstract

A key advantage in mouse molecular genetics is the ability to tailor transgene expression to particular tissues at particular times in development. Such ability allows for increasingly more sophisticated analysis of gene function and detailed understanding of developmental fates, and the molecular and cellular mechanisms underlying those fates. These methodologies rely on germ-line manipulations in mouse embryos and are not directly applicable to other models of development, such as chick embryogenesis. Dr. Ragsdale and his coworkers will explore a more broadly applicable method of heritable, conditional transgenesis, one that could be used in a range of animal embryos. Avian retroviruses have a restricted host range, and even among chickens there are strains of birds that are susceptible to infection by only certain viral subgroups. The relevant viral receptors have now been cloned and can confer viral infectivity to heterologous cells. In addition, in a growing number of experimental systems, transient transgenesis can be achieved by direct tissue electroporation of embryos. Dr. Ragsdale will develop a transgenesis system in which electroporation delivers avian retroviral receptors for transient misexpression. The location and timing of the exogenous receptor expression is controlled by the time and site of the electroporation and can be further restricted by tissue-specific promoters. Subsequent retroviral infection then provides for heritable transgene delivery only to those cells expressing the viral receptor at the time of the infection. Dr. Ragsdale will explore this system in chick neural development, but its applicability is potentially much broader and includes the range of embryos, from ascidians to mice, where in vivo electroporation can be used to introduce plasmid DNA into developing organs.