Hox Genes During Embryogenesis

A long-term goal of the Gebelein Laboratory is to understand how specialized cell types are specified by the Hox transcription factors during embryogenesis. Organisms ranging from worms to humans encode a set of conserved Hox genes, each of which encodes a transcription factor that is differentially expressed along the developing anterior–-posterior axis to specify the identity of distinct body regions (head, thorax, abdomen).

In principle, each Hox transcription factor performs this task by regulating the expression of unique sets of downstream target genes required for the different body regions to develop the appropriate organs and tissues. For example, vertebrates contain 39 Hox genes that participate in the developmental control of the nervous system, the skeletal system, the gastrointestinal system, the urogenital system, the blood system, and the limbs.

How each Hox transcription factor directs the appropriate formation of different cell types within so many organ systems is currently not clear. Moreover, mutations and / or mis-expression of Hox factors can cause limb malformations as well as leukemias and cancers through pathways that are not well understood.

Our laboratory uses a combination of genetics, biochemistry, cell culture, and bioinformatics to understand how Hox factors are integrated with additional tissue and organ specific transcription factors to direct distinct cell fates in Drosophila melanogaster.

In particular, our laboratory has projects focused on the following fundamental problems:
1) The regulation of neuronal gene expression
2) The molecular control of organ size
3) The specification of appendages
4) The control of organismal growth