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Research
Current Projects by Principal Investigator
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Research
Verena Göbel  , MD
Assistant Professor of Pediatrics
Phone: 617-726-4171
Fax: 617-726-4172
Email: gobel@helix.mgh.harvard.edu
Curriculum Vita
The laboratory is interested in cell shape formation and organ morphogenesis, and in the mechanisms required to construct and maintain complex three-dimensional structures. It has long been speculated that morphogenesis and proliferation share regulatory networks, and we are particularly interested in defining the relationship between epithelial morphogenesis and growth regulation. As basic biological processes and complex signaling pathways are highly conserved throughout evolution, we are using the simple nematode C. elegans to investigate this process. C. elegans is particularly well suited for the study of morphogenesis, since the development of its tissues can be observed in the transparent animal, and its cell lineage is invariant, with the position and fate of every cell mapped throughout the life of the animal. In addition, its sophisticated genetics and short reproductive cycle facilitate the use of genetic screens, a powerful means to identify functionally relevant protein interactions.
We have recently assessed the role of C. elegans orthologs of cytoskeletal tumor suppressor and oncogenes as potential master regulators at the junction of morphogenesis and growth. We are particularly interested in a class of putative cytoskeleton-regulating molecules that are structurally characterized by their FERM-domain (protein 4.1-ezrin-radixin-moesin-membrane-linking domain). Human ezrin, radixin, moesin (ERM) and their C. elegans ortholog erm-1, and human merlin/schwannomin (Neurofibromatosis 2) and its C. elegans ortholog nfm-1, are members of this family. There are ten additional FERM-domain genes in C. elegans (frm-1-10). erm-1 is an apical molecule essential for tubulogenesis of the intestine, the excretory canals and the gonad. We plan to continue to investigate the mechanism by which erm-1 shapes the apical membrane and its microdomains, to identify the molecules with which it accomplishes this task, and to define its transcriptional regulation. To this effect, we are using high-resolution microscopic techniques, genetic suppressor/enhancer screens, and mutational analysis. We are also continuing to characterize nfm-1, which is localized basolaterally and apparently has a complementary role to erm-1 in the morphogenesis of tubular epithelia, including the intestine. frm-3, the ortholog of CDEP (chondrocyte-derived ezrin-like domain containing protein), is another FERM-domain gene we have been investigating.
To complement these reverse genetic approaches, we are also undertaking a forward, genome-wide RNA interference (RNAi) screen on C. elegans tubulogenesis, to identify novel genes required for this process. The transparent roundworm lends itself to such a screen, being composed of simple yet distinct tubular organ structures. For example, the intestine is a single-layered epithelial tube, invariably constructed by twenty cells arranged in bilateral symmetry, while the intricate excretory canal system is intra-cellularly generated from one single cell. Using a candidate RNAi approach in a pilot phase, we have already identified C. elegans act-5/cytoplasmic actin and sma-1/ß-H-spectrin as molecules required for lumen morphogenesis in both these epithelia. act-5, like erm-1, shapes and stabilizes the luminal scaffold of the intestine, and is required for the formation of intestinal microvilli. This genome-wide screen should identify most genes required for the development of the intestine. It is hoped, that genes and phenotypes identified in this screen will lead us back to human diseases, such as inherited intestinal failure syndromes where the underlying genetic defects have not yet been identified.
The need to generate germline deletions in specific C. elegans orthologs and the need to clone genes isolated in forward screens, has made the development of gene deletion/targeting and cloning approaches a separate, but related interest of the laboratory. We have recently described a targeted gene alteration technique, using transposon-dependent gene conversion. We have also designed a strategy to use high-throughput techniques for cloning the underlying gene defects of mutants identified in forward genetic screens that awaits further testing. With some modification, these techniques should also be applicable for gene alteration and cloning in other species, including the cloning of human disease genes.
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