Chris Q. Doe

Prox 1, a prospero-related homeobox gene expressed during mouse development.

Prox 1, a likely mouse homologue of the Drosophila homeobox gene prospero has been cloned and its expression pattern analyzed during development. In Drosophila, prospero is expressed in the developing CNS, lens-secreting cone cells of the eye, and midgut. In the mouse, Prox 1 is expressed in many of the same tissues: young neurons of the subventricular region of the CNS, developing eye lens and pancreas. Expression is also detected in the developing liver and heart, as well as transiently in the skeletal muscles. The similarities in protein sequence and expression patterns between the mouse and fly cognate genes suggest that Prox 1 may play, among others, a fundamental role in early development of the murine CNS.

Identification and cell lineage of individual neural precursors in the Drosophila CNS

The Drosophila CNS is complex enough to serve as a model for many of the molecular, cellular and developmental functions of the vertebrate CNS, yet simple enough for single-cell analysis. Recent advances have provided molecular markers that allow most Drosophila CNS precursors to be uniquely identified, as well as methods for determining the complete cell lineage of each precursor. A detailed understanding of wild-type neurogenesis, combined with existing molecular genetic techniques, should provide insight into the fundamental mechanisms that generate neuronal and glial diversity.

Segmentation and homeotic gene function in the developing nervous system of Drosophila

Abstract Segmentation and homeotic genes of the fruit fly Drosophila control the pattern and identity of segments in the embryonic and adult epidermis. Most of these genes are also expressed in the developing nervous system, as are related vertebrate genes. Recent evidence suggests that segmentation genes are required for early steps in neuronal determination, whereas homeotic genes control segment-specific neuronal differences.

TheengrailedandhuckebeinGenes Are Essential for Development of Serotonin Neurons in theDrosophilaCNS

A number of the pattern formation genes expressed in the Drosophila epidermis are also expressed in the developing CNS. It is uncertain how these genes contribute to neuronal differentiation. Here we show that the normal differentiation of the serotonin neurons of the Drosophila nerve cord is dependent on the expression of two pattern formation genes, huckebein (hkb) and engrailed (en). hkb and en gene products coexpress uniquely in the serotonin neurons and in neuroblast 7-3 (NB 7-3), indicating that as in the grasshopper, NB 7-3 is the progenitor for these neurons. Both genes are important for differentiation of this lineage, since loss-of-function alleles for hkb or en eliminate expression of several markers that characterize these cells. hkb appears to act at a step subsequent to NB delamination, since NB 7-3 is detectable in a strain containing a severe hkb allele.

Asymmetric cell division and neurogenesis

Several proteins have been identified that are asymmetrically localized in dividing Drosophila and vertebrate neural precursors. Some are involved in establishing cell polarity, whereas others are determinants of cell fate. New insights into how cell diversity is generated during neurogenesis have been obtained and the means for rapid progress in this field now exist.