Neural stem cell biology in vertebrates and invertebrates: more alike than different?

Many of the regulatory mechanisms controlling neural stem cell behavior are proving to be conserved between organisms as diverse as worms and man. Common principles are emerging with respect to the regulation of neural stem cell division and the specification of distinct stem and progenitor cell types. Great progress has been made in recent years in identifying the cellular mechanisms underpinning these processes, thanks in large part to the cross-fertilization of research on different model systems. We review here recent findings that highlight hitherto unappreciated similarities in the cell and molecular biology of neural stem cell self-renewal and differentiation between invertebrates and vertebrates. As well as underscoring the possible conservation of stem cell mechanisms across phyla, these similarities are proving to be practically useful in studying neural stem cell biology in health and disease.