Cancers of the digestive tract are a leading cause of cancer related deaths in the United States. Since the majority of these tumors are of epithelial origin characterization of the cellular processes which regulate epithelial renewal in these organs is essential for understanding their malignant transformation. Genetic analyses are particularly suited to the dissection of complex regulatory pathways and for this reason we have begun a molecular analysis of intestinal epithelial renewal using the zebrafish. The zebrafish is the only vertebrate in which large scale forward genetics is feasible and through chemical mutagenesis we have discovered a group of novel mutations which perturb epithelial development in the digestive organs of this organism. From this group of mutants we have defined two mutations, slimjim and meltdown that appear to regulate events in the zebrafish intestinal epithelium that are crucial for orderly renewal of cells in the intestine of mammals. Since only a small number of mammalian genes are known to contribute to the process of epithelial renewal we have designed a strategy for the molecular characterization of the genes responsible for slimjim and meltdown. Both mutations were discovered through chemical mutagenesis so their molecular characterization is dependent upon positional cloning, a complex process but one for which the zebrafish is well suited. In this proposal we outline a strategy for the identification of the slimjim and meltdown genes using positional cloning.
Our first aim i s to identify molecular markers tightly linked to each mutant locus using the Amplified Fragment Length Polymorphism technique (AFLP). Next we will use these markers to generate a physical map of this region of the genome by identifying overlapping contigs from a bacterial artificial chromosome (BAC) library screened with the genetic markers. Using these BAC clones we will further narrow the size of the mutant loci and then identify transcripts from this region using cDNA selection, BAC screening of cDNA libraries, and sequencing of BAC clones. From these candidates the responsible gene will be identified through transcript analysis, sequencing and mutant rescue using BAC clones. An additional aim of this work is to generate new alleles of each mutation using gamma-irradiation, an efficient mutagen in zebrafish. The gamma-alleles

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
3R01DK054942-01A1S1
Application #
6294687
Study Section
General Medicine A Subcommittee 2 (GMA)
Program Officer
May, Michael K
Project Start
1999-08-01
Project End
2003-07-31
Budget Start
2000-05-01
Budget End
2000-07-31
Support Year
1
Fiscal Year
2000
Total Cost
$41,259
Indirect Cost
Name
University of Pennsylvania
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
042250712
City
Philadelphia
State
PA
Country
United States
Zip Code
19104
Abrams, Joshua; Einhorn, Zev; Seiler, Christoph et al. (2016) Graded effects of unregulated smooth muscle myosin on intestinal architecture, intestinal motility and vascular function in zebrafish. Dis Model Mech 9:529-40
Seiler, Christoph; Davuluri, Gangarao; Abrams, Joshua et al. (2012) Smooth muscle tension induces invasive remodeling of the zebrafish intestine. PLoS Biol 10:e1001386
Walters, James W; Anderson, Jennifer L; Bittman, Robert et al. (2012) Visualization of lipid metabolism in the zebrafish intestine reveals a relationship between NPC1L1-mediated cholesterol uptake and dietary fatty acid. Chem Biol 19:913-25
Abrams, J; Davuluri, G; Seiler, C et al. (2012) Smooth muscle caldesmon modulates peristalsis in the wild type and non-innervated zebrafish intestine. Neurogastroenterol Motil 24:288-99
Gao, Nan; Davuluri, Gangarao; Gong, Weilong et al. (2011) The nuclear pore complex protein Elys is required for genome stability in mouse intestinal epithelial progenitor cells. Gastroenterology 140:1547-55.e10
Seiler, Christoph; Pack, Michael (2011) Transgenic labeling of the zebrafish pronephric duct and tubules using a promoter from the enpep gene. Gene Expr Patterns 11:118-21
Lorent, Kristin; Moore, John C; Siekmann, Arndt F et al. (2010) Reiterative use of the notch signal during zebrafish intrahepatic biliary development. Dev Dyn 239:855-64
Clifton, Justin D; Lucumi, Edinson; Myers, Michael C et al. (2010) Identification of novel inhibitors of dietary lipid absorption using zebrafish. PLoS One 5:e12386
Seiler, Christoph; Abrams, Joshua; Pack, Michael (2010) Characterization of zebrafish intestinal smooth muscle development using a novel sm22?-b promoter. Dev Dyn 239:2806-12
Davuluri, G; Seiler, C; Abrams, J et al. (2010) Differential effects of thin and thick filament disruption on zebrafish smooth muscle regulatory proteins. Neurogastroenterol Motil 22:1100-e285

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