Specific research topics in our lab include:

• Signaling pathway function and crosstalks
• Tissue morphogenesis
• Transcriptional regulation
• Cancer genetics
• C. briggsae linkage maps (read here)
• Functional genomics in Caenorhabditis nematodes
• Neurobiology and drug discovery (read more about it here)

Development and function of multicellular organisms requires coordinated actions of many genes that interact with each other and are expressed in dynamic patterns. Alterations in gene networks can cause many abnormalities including cancers and neuronal degeneration. Hence, understanding spatiotemporal controls of gene interactions is critical to gaining important insights into the pathogenesis of human diseases.

Toward this goal we are investigating three conserved biological processes, namely, cell signaling, cell proliferation and differentiation, in two well-established model organisms (nematodes or worms), C. elegans and C. briggsae. These two species offer many experimental advantages including rapid development (~3 days from egg to adult), transparency, small (~1 mm), hermaphroditic life style, and compact genome (~100 megabases). Approximately two-thirds of the genes in worms have human homologs and many of the gene function and cellular and molecular processes are conserved all the way to human.

A major part of our research focuses on the reproductive system, specifically the vulva, an organ that serves as a passageway for mating and laying eggs. In C. elegans vulva is formed by the progeny of three out of six multipotential vulval precursor cells (VPCs) that divide three times to give rise to twenty-two cells. The vulval progeny differentiate during L4 larval stage to generate seven different cell types leading to the formation of an adult vulva. The invariant lineage of the VPCs and stereotypic positions of their progeny offer experimental analyses at single-cell resolution.

One of the projects involves investigating the regulation and function of a LIM homeobox transcription factor LIN-11. LIN-11 is a key regulator of vulval morphogenesis. In lin-11 mutant animals, vulval cells fail to acquire correct identities and inappropriately fuse with each other (Gupta et.al, 2003). Thus, lin-11 confers cell identity by regulating the expression of cell type-specific genes. We are taking a variety of approaches in Genetics, Molecular Biology and Bioinformatics to understand the molecular basis of lin-11 regulation and its downstream targets during vulval morphogenesis.

Another project deals with the regulation of Wnt Signal transduction pathway. Wnt proteins form a family of highly conserved secreted signaling molecules that regulate cell-to-cell interactions during embryogenesis. Insights into the mechanisms of Wnt action have emerged from several systems: genetics in Drosophila and C. elegans; biochemistry in cell culture and ectopic gene expression in Xenopus embryos. Mutations in Wnt genes or Wnt pathway components lead to specific developmental defects, while various human diseases, including cancer, are caused by abnormal Wnt signaling. As currently understood, Wnt proteins bind to receptors of the Frizzled and LRP families on the cell surface. Through several cytoplasmic relay components, the signal is transduced to beta-catenin, which enters the nucleus and forms a complex with TCF to activate transcription of Wnt target genes.

Our lab is also investigating the electrotaxis sensory behavior in nematodes. In collaboration with Ravi Selvaganapathy (Mechanical Engineering, McMaster University) we provided the first evidence of electrotaxis response in C. elegans in a microfluidic channel environment (Rezai et al., Lab Chip 2010). We showed that a DC electric field stimulus induces the worm to swim towards cathode with a characteristic speed that is robust, instantaneous and highly sensitive. Subsequently, we demonstrated that dopamine (DA) neurons play important role in mediating the electrotaxis behavior. The involvement of DA signalling has allowed us to model Parkinson's disease in C. elegans, in order to understand the mechanism of neurodegeneration and to identify neuorprotective chemicals.